diff --git a/orm/models_utils.go b/orm/models_utils.go
index ec11d516..1dc17f81 100644
--- a/orm/models_utils.go
+++ b/orm/models_utils.go
@@ -192,10 +192,10 @@ func parseStructTag(data string, attrs *map[string]bool, tags *map[string]string
 	tag := make(map[string]string)
 	for _, v := range strings.Split(data, defaultStructTagDelim) {
 		v = strings.TrimSpace(v)
-		if supportTag[v] == 1 {
-			attr[v] = true
+		if t := strings.ToLower(v); supportTag[t] == 1 {
+			attr[t] = true
 		} else if i := strings.Index(v, "("); i > 0 && strings.Index(v, ")") == len(v)-1 {
-			name := v[:i]
+			name := t[:i]
 			if supportTag[name] == 2 {
 				v = v[i+1 : len(v)-1]
 				tag[name] = v
diff --git a/orm/orm_test.go b/orm/orm_test.go
index 11f6bd56..c029999f 100644
--- a/orm/orm_test.go
+++ b/orm/orm_test.go
@@ -2117,3 +2117,47 @@ func TestUintPk(t *testing.T) {
 
 	dORM.Delete(u)
 }
+
+func TestSnake(t *testing.T) {
+	cases := map[string]string{
+		"i":           "i",
+		"I":           "i",
+		"iD":          "i_d",          //01
+		"ID":          "id",           //11  pre+curent=2
+		"NO":          "no",           //11
+		"NOO":         "noo",          //111   10
+		"NOOooOOoo":   "noo_oo_oo_oo", //111_00_11_00
+		"OrderNO":     "order_no",     //10000_11
+		"tagName":     "tag_name",     //000_1000
+		"tag_Name":    "tag_name",
+		"tag_name":    "tag_name",
+		"_tag_name":   "_tag_name",
+		"tag_666name": "tag_666name",
+		"tag_666Name": "tag_666_name",
+	}
+	for name, want := range cases {
+		got := snakeString(name)
+		throwFail(t, AssertIs(got, want))
+	}
+}
+
+func TestIgnoreCaseTag(t *testing.T) {
+	type testTagModel struct {
+		ID     int    `orm:"pk"`
+		NOO    string `orm:"column(n)"`
+		Name01 string `orm:"NULL"`
+		Name02 string `orm:"COLUMN(Name)"`
+		Name03 string `orm:"Column(name)"`
+	}
+	RegisterModel(&testTagModel{})
+	info, ok := modelCache.get("test_tag_model")
+	throwFail(t, AssertIs(ok, true))
+	throwFail(t, AssertNot(info, nil))
+	if t == nil {
+		return
+	}
+	throwFail(t, AssertIs(info.fields.GetByName("NOO").column, "n"))
+	throwFail(t, AssertIs(info.fields.GetByName("Name01").null, true))
+	throwFail(t, AssertIs(info.fields.GetByName("Name02").column, "Name"))
+	throwFail(t, AssertIs(info.fields.GetByName("Name03").column, "name"))
+}
diff --git a/orm/utils.go b/orm/utils.go
index 99437c7b..e3cd8ad6 100644
--- a/orm/utils.go
+++ b/orm/utils.go
@@ -181,18 +181,36 @@ func ToInt64(value interface{}) (d int64) {
 	return
 }
 
-// snake string, XxYy to xx_yy
+// snake string, XxYy to xx_yy , XxYY to xx_yy
 func snakeString(s string) string {
 	data := make([]byte, 0, len(s)*2)
-	j := false
 	num := len(s)
 	for i := 0; i < num; i++ {
 		d := s[i]
-		if i > 0 && d >= 'A' && d <= 'Z' && j {
-			data = append(data, '_')
-		}
-		if d != '_' {
-			j = true
+		if i > 0 && d != '_' && s[i-1] != '_' {
+			need := false
+			// upper as 1, lower as 0
+			// 		XX -> 11 -> 11
+			// 		Xx -> 10 -> 10
+			//		XxYyZZ -> 101011 -> 10_10_11
+			isUpper := d >= 'A' && d <= 'Z'
+			preIsUpper := s[i-1] >= 'A' && s[i-1] <= 'Z'
+			if isUpper {
+				// like : xxYy
+				if !preIsUpper {
+					need = true
+				}
+			} else {
+				if preIsUpper {
+					// ignore "Xy" in "xxXyy"
+					if i-2 >= 0 && s[i-2] >= 'A' && s[i-2] <= 'Z' {
+						need = true
+					}
+				}
+			}
+			if need {
+				data = append(data, '_')
+			}
 		}
 		data = append(data, d)
 	}