diff --git a/checker.go b/checker.go
index 99e65bb..f92ba8f 100644
--- a/checker.go
+++ b/checker.go
@@ -9,28 +9,28 @@ import (
 )
 
 // 检查ID参数
-func CheckIdArgument(id string) bool {
-	_, err := GenerateCode(id)
+func checkIdArgument(id string) bool {
+	_, err := generateCode(id)
 
 	return err == nil
 }
 
 // 生成数据
-func GenerateCode(id string) (map[string]string, error) {
+func generateCode(id string) (map[string]string, error) {
 	length := len(id)
 	if length == 15 {
-		return GenerateShortCode(id)
+		return generateShortCode(id)
 	}
 
 	if length == 18 {
-		return GenerateLongCode(id)
+		return generateLongCode(id)
 	}
 
 	return map[string]string{}, errors.New("Invalid ID card number length.")
 }
 
 // 生成短数据
-func GenerateShortCode(id string) (map[string]string, error) {
+func generateShortCode(id string) (map[string]string, error) {
 	if len(id) != 15 {
 		return map[string]string{}, errors.New("Invalid ID card number length.")
 	}
@@ -49,7 +49,7 @@ func GenerateShortCode(id string) (map[string]string, error) {
 }
 
 // 生成长数据
-func GenerateLongCode(id string) (map[string]string, error) {
+func generateLongCode(id string) (map[string]string, error) {
 	if len(id) != 18 {
 		return map[string]string{}, errors.New("Invalid ID card number length.")
 	}
@@ -67,13 +67,13 @@ func GenerateLongCode(id string) (map[string]string, error) {
 }
 
 // 检查地址码
-func CheckAddressCode(addressCode string, birthdayCode string) bool {
-	return GetAddressInfo(addressCode, birthdayCode)["province"] != ""
+func checkAddressCode(addressCode string, birthdayCode string) bool {
+	return getAddressInfo(addressCode, birthdayCode)["province"] != ""
 }
 
 // 检查出生日期码
-func CheckBirthdayCode(birthdayCode string) bool {
-	year, _ := strconv.Atoi(Substr(birthdayCode, 0, 4))
+func checkBirthdayCode(birthdayCode string) bool {
+	year, _ := strconv.Atoi(substr(birthdayCode, 0, 4))
 	if year < 1800 {
 		return false
 	}
@@ -89,6 +89,6 @@ func CheckBirthdayCode(birthdayCode string) bool {
 }
 
 // 检查顺序码
-func CheckOrderCode(orderCode string) bool {
+func checkOrderCode(orderCode string) bool {
 	return len(orderCode) == 3
 }
diff --git a/generator.go b/generator.go
index 8394093..0279130 100644
--- a/generator.go
+++ b/generator.go
@@ -11,7 +11,7 @@ import (
 )
 
 // 生成Bit码
-func GeneratorCheckBit(body string) string {
+func generatorCheckBit(body string) string {
 	// 位置加权
 	var posWeight [19]float64
 	for i := 2; i < 19; i++ {
@@ -37,7 +37,7 @@ func GeneratorCheckBit(body string) string {
 }
 
 // 生成地址码
-func GeneratorAddressCode(address string) string {
+func generatorAddressCode(address string) string {
 	addressCode := ""
 	for code, addressStr := range data.AddressCode {
 		if address == addressStr {
@@ -46,45 +46,45 @@ func GeneratorAddressCode(address string) string {
 		}
 	}
 
-	classification := AddressCodeClassification(addressCode)
+	classification := addressCodeClassification(addressCode)
 	switch classification {
 	case "country":
-		// addressCode = GetRandAddressCode("\\d{4}(?!00)[0-9]{2}$")
-		addressCode = GetRandAddressCode("\\d{4}(?)[0-9]{2}$")
+		// addressCode = getRandAddressCode("\\d{4}(?!00)[0-9]{2}$")
+		addressCode = getRandAddressCode("\\d{4}(?)[0-9]{2}$")
 	case "province":
-		provinceCode := Substr(addressCode, 0, 2)
+		provinceCode := substr(addressCode, 0, 2)
 		// pattern := "^" + provinceCode + "\\d{2}(?!00)[0-9]{2}$"
 		pattern := "^" + provinceCode + "\\d{2}(?)[0-9]{2}$"
-		addressCode = GetRandAddressCode(pattern)
+		addressCode = getRandAddressCode(pattern)
 	case "city":
-		cityCode := Substr(addressCode, 0, 4)
+		cityCode := substr(addressCode, 0, 4)
 		// pattern := "^" + cityCode + "(?!00)[0-9]{2}$"
 		pattern := "^" + cityCode + "(?)[0-9]{2}$"
-		addressCode = GetRandAddressCode(pattern)
+		addressCode = getRandAddressCode(pattern)
 	}
 
 	return addressCode
 }
 
 // 地址码分类
-func AddressCodeClassification(addressCode string) string {
+func addressCodeClassification(addressCode string) string {
 	// 全国
 	if addressCode == "" {
 		return "country"
 	}
 
 	// 港澳台
-	if Substr(addressCode, 0, 1) == "8" {
+	if substr(addressCode, 0, 1) == "8" {
 		return "special"
 	}
 
 	// 省级
-	if Substr(addressCode, 2, 6) == "0000" {
+	if substr(addressCode, 2, 6) == "0000" {
 		return "province"
 	}
 
 	// 市级
-	if Substr(addressCode, 4, 6) == "00" {
+	if substr(addressCode, 4, 6) == "00" {
 		return "city"
 	}
 
@@ -93,12 +93,12 @@ func AddressCodeClassification(addressCode string) string {
 }
 
 // 获取随机地址码
-func GetRandAddressCode(pattern string) string {
+func getRandAddressCode(pattern string) string {
 	mustCompile := regexp.MustCompile(pattern)
 	var keys []string
 	for key := range data.AddressCode {
 		keyStr := strconv.Itoa(key)
-		if mustCompile.MatchString(keyStr) && Substr(keyStr, 4, 6) != "00" {
+		if mustCompile.MatchString(keyStr) && substr(keyStr, 4, 6) != "00" {
 			keys = append(keys, keyStr)
 		}
 	}
@@ -109,25 +109,25 @@ func GetRandAddressCode(pattern string) string {
 }
 
 // 生成出生日期码
-func GeneratorBirthdayCode(birthday string) string {
-	year := DatePipelineHandle(DatePad(Substr(birthday, 0, 4), "year"), "year")
-	month := DatePipelineHandle(DatePad(Substr(birthday, 4, 6), "month"), "month")
-	day := DatePipelineHandle(DatePad(Substr(birthday, 6, 8), "day"), "day")
+func generatorBirthdayCode(birthday string) string {
+	year := datePipelineHandle(datePad(substr(birthday, 0, 4), "year"), "year")
+	month := datePipelineHandle(datePad(substr(birthday, 4, 6), "month"), "month")
+	day := datePipelineHandle(datePad(substr(birthday, 6, 8), "day"), "day")
 
 	birthday = year + month + day
 	_, error := time.Parse("20060102", birthday)
 	// example: 195578
 	if error != nil {
-		year = DatePad(year, "year")
-		month = DatePad(month, "month")
-		day = DatePad(day, "day")
+		year = datePad(year, "year")
+		month = datePad(month, "month")
+		day = datePad(day, "day")
 	}
 
 	return year + month + day
 }
 
 // 日期处理
-func DatePipelineHandle(date string, category string) string {
+func datePipelineHandle(date string, category string) string {
 	dateInt, _ := strconv.Atoi(date)
 
 	switch category {
@@ -155,7 +155,7 @@ func DatePipelineHandle(date string, category string) string {
 }
 
 // 生成顺序码
-func GeneratorOrderCode(sex int) string {
+func generatorOrderCode(sex int) string {
 	rand.Seed(time.Now().Unix())
 	orderCode := rand.Intn(999-111) + 111
 	if sex != orderCode%2 {
@@ -166,7 +166,7 @@ func GeneratorOrderCode(sex int) string {
 }
 
 // 日期补全
-func DatePad(date string, category string) string {
+func datePad(date string, category string) string {
 	padLength := 2
 	if category == "year" {
 		padLength = 4
diff --git a/helper.go b/helper.go
index 9ae7ff8..7dd26ca 100644
--- a/helper.go
+++ b/helper.go
@@ -6,8 +6,8 @@ import (
 	"strings"
 )
 
-// 检查地址码
-func GetAddressInfo(addressCode string, birthdayCode string) map[string]string {
+// 获取地址信息
+func getAddressInfo(addressCode string, birthdayCode string) map[string]string {
 	addressInfo := map[string]string{
 		"province": "",
 		"city":     "",
@@ -15,29 +15,29 @@ func GetAddressInfo(addressCode string, birthdayCode string) map[string]string {
 	}
 
 	// 省级信息
-	addressInfo["province"] = GetAddress(Substr(addressCode, 0, 2)+"0000", birthdayCode)
+	addressInfo["province"] = getAddress(substr(addressCode, 0, 2)+"0000", birthdayCode)
 
 	// 用于判断是否是港澳台居民居住证（8字开头）
-	firstCharacter := Substr(addressCode, 0, 1)
+	firstCharacter := substr(addressCode, 0, 1)
 	// 港澳台居民居住证无市级、县级信息
 	if firstCharacter == "8" {
 		return addressInfo
 	}
 
 	// 市级信息
-	addressInfo["city"] = GetAddress(Substr(addressCode, 0, 4)+"00", birthdayCode)
+	addressInfo["city"] = getAddress(substr(addressCode, 0, 4)+"00", birthdayCode)
 
 	// 县级信息
-	addressInfo["district"] = GetAddress(addressCode, birthdayCode)
+	addressInfo["district"] = getAddress(addressCode, birthdayCode)
 
 	return addressInfo
 }
 
 // 获取省市区地址码
-func GetAddress(addressCode string, birthdayCode string) string {
+func getAddress(addressCode string, birthdayCode string) string {
 	address := ""
 	addressCodeInt, _ := strconv.Atoi(addressCode)
-	year, _ := strconv.Atoi(Substr(birthdayCode, 0, 4))
+	year, _ := strconv.Atoi(substr(birthdayCode, 0, 4))
 	for key, val := range data.AddressCodeTimeline[addressCodeInt] {
 		// if len(val) == 0 {
 		// 	continue
@@ -52,9 +52,9 @@ func GetAddress(addressCode string, birthdayCode string) string {
 }
 
 // 获取星座信息
-func GetConstellation(birthdayCode string) string {
-	monthStr := Substr(birthdayCode, 4, 6)
-	dayStr := Substr(birthdayCode, 6, 8)
+func getConstellation(birthdayCode string) string {
+	monthStr := substr(birthdayCode, 4, 6)
+	dayStr := substr(birthdayCode, 6, 8)
 	month, _ := strconv.Atoi(monthStr)
 	day, _ := strconv.Atoi(dayStr)
 	startDate := data.Constellation[month]["start_date"]
@@ -72,17 +72,17 @@ func GetConstellation(birthdayCode string) string {
 }
 
 // 获取生肖信息
-func GetChineseZodiac(birthdayCode string) string {
+func getChineseZodiac(birthdayCode string) string {
 	// 子鼠
 	start := 1900
-	end, _ := strconv.Atoi(Substr(birthdayCode, 0, 4))
+	end, _ := strconv.Atoi(substr(birthdayCode, 0, 4))
 	key := (end - start) % 12
 
 	return data.ChineseZodiac[key]
 }
 
-// Substr 截取字符串
-func Substr(source string, start int, end int) string {
+// substr 截取字符串
+func substr(source string, start int, end int) string {
 	r := []rune(source)
 	length := len(r)
 
diff --git a/id_validator.go b/id_validator.go
index 739c53d..dad6b85 100644
--- a/id_validator.go
+++ b/id_validator.go
@@ -9,7 +9,7 @@ import (
 )
 
 // 身份证信息
-type IdInfo struct {
+type idInfo struct {
 	AddressCode   int
 	Abandoned     int
 	Address       string
@@ -24,13 +24,13 @@ type IdInfo struct {
 
 // 验证身份证号合法性
 func IsValid(id string) bool {
-	code, err := GenerateCode(id)
+	code, err := generateCode(id)
 	if err != nil {
 		return false
 	}
 
 	// 检查顺序码、生日码、地址码
-	if !CheckOrderCode(code["order"]) || !CheckBirthdayCode(code["birthdayCode"]) || !CheckAddressCode(code["addressCode"], code["birthdayCode"]) {
+	if !checkOrderCode(code["order"]) || !checkBirthdayCode(code["birthdayCode"]) || !checkAddressCode(code["addressCode"], code["birthdayCode"]) {
 		return false
 	}
 
@@ -40,21 +40,21 @@ func IsValid(id string) bool {
 	}
 
 	// 校验码
-	return code["checkBit"] == GeneratorCheckBit(code["body"])
+	return code["checkBit"] == generatorCheckBit(code["body"])
 }
 
 // 获取身份证信息
-func GetInfo(id string) (IdInfo, error) {
+func GetInfo(id string) (idInfo, error) {
 	// 验证有效性
 	if !IsValid(id) {
-		return IdInfo{}, errors.New("Not Valid ID card number.")
+		return idInfo{}, errors.New("Not Valid ID card number.")
 	}
 
-	code, _ := GenerateCode(id)
+	code, _ := generateCode(id)
 	addressCode, _ := strconv.Atoi(code["addressCode"])
 
 	// 地址信息
-	addressInfo := GetAddressInfo(code["addressCode"], code["birthdayCode"])
+	addressInfo := getAddressInfo(code["addressCode"], code["birthdayCode"])
 	var addressTree []string
 	for _, val := range addressInfo {
 		addressTree = append(addressTree, val)
@@ -79,14 +79,14 @@ func GetInfo(id string) (IdInfo, error) {
 	// 长度
 	length, _ := strconv.Atoi(code["type"])
 
-	return IdInfo{
+	return idInfo{
 		AddressCode:   addressCode,
 		Abandoned:     abandoned,
 		Address:       addressInfo["province"] + addressInfo["city"] + addressInfo["district"],
 		AddressTree:   addressTree,
 		Birthday:      birthday,
-		Constellation: GetConstellation(code["birthdayCode"]),
-		ChineseZodiac: GetChineseZodiac(code["birthdayCode"]),
+		Constellation: getConstellation(code["birthdayCode"]),
+		ChineseZodiac: getChineseZodiac(code["birthdayCode"]),
 		Sex:           sex,
 		Length:        length,
 		CheckBit:      code["checkBit"],
@@ -105,21 +105,21 @@ func FakeId() string {
 // sex        性别：1为男性，0为女性
 func FakeRequireId(isEighteen bool, address string, birthday string, sex int) string {
 	// 生成地址码
-	addressCode := GeneratorAddressCode(address)
+	addressCode := generatorAddressCode(address)
 
 	// 出生日期码
-	birthdayCode := GeneratorBirthdayCode(birthday)
+	birthdayCode := generatorBirthdayCode(birthday)
 
 	// 生成顺序码
-	orderCode := GeneratorOrderCode(sex)
+	orderCode := generatorOrderCode(sex)
 
 	if !isEighteen {
-		return addressCode + Substr(birthdayCode, 2, 8) + orderCode
+		return addressCode + substr(birthdayCode, 2, 8) + orderCode
 	}
 
 	body := addressCode + birthdayCode + orderCode
 
-	return body + GeneratorCheckBit(body)
+	return body + generatorCheckBit(body)
 }
 
 // 15位升级18位号码
@@ -128,9 +128,9 @@ func UpgradeId(id string) (string, error) {
 		return "", errors.New("Not Valid ID card number.")
 	}
 
-	code, _ := GenerateShortCode(id)
+	code, _ := generateShortCode(id)
 
 	body := code["addressCode"] + code["birthdayCode"] + code["order"]
 
-	return body + GeneratorCheckBit(body), nil
+	return body + generatorCheckBit(body), nil
 }