diff --git a/orm/orm_test.go b/orm/orm_test.go
index 75a60cb0..bb1831f9 100644
--- a/orm/orm_test.go
+++ b/orm/orm_test.go
@@ -2135,13 +2135,13 @@ func TestSnake(t *testing.T) {
 		"i":           "i",
 		"I":           "i",
 		"iD":          "i_d",
-		"ID":          "id",
-		"NO":          "no",
-		"NOO":         "noo",
-		"NOOooOOoo":   "noo_oo_oo_oo",
-		"OrderNO":     "order_no",
+		"ID":          "i_d",
+		"NO":          "n_o",
+		"NOO":         "n_o_o",
+		"NOOooOOoo":   "n_o_ooo_o_ooo",
+		"OrderNO":     "order_n_o",
 		"tagName":     "tag_name",
-		"tag_Name":    "tag_name",
+		"tag_Name":    "tag__name",
 		"tag_name":    "tag_name",
 		"_tag_name":   "_tag_name",
 		"tag_666name": "tag_666name",
diff --git a/orm/utils.go b/orm/utils.go
index e3cd8ad6..6e23447e 100644
--- a/orm/utils.go
+++ b/orm/utils.go
@@ -184,33 +184,15 @@ func ToInt64(value interface{}) (d int64) {
 // 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 != '_' && 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, '_')
-			}
+		if i > 0 && d >= 'A' && d <= 'Z' && j {
+			data = append(data, '_')
+		}
+		if d != '_' {
+			j = true
 		}
 		data = append(data, d)
 	}