diff --git a/strutil/string.go b/strutil/string.go
index a4dcadd..2498345 100644
--- a/strutil/string.go
+++ b/strutil/string.go
@@ -121,37 +121,45 @@ func UpperSnakeCase(s string) string {
 
 // Before create substring in source string before position when char first appear
 func Before(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.Index(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.Index(s, char)
+
 	return s[0:i]
 }
 
 // BeforeLast create substring in source string before position when char last appear
 func BeforeLast(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.LastIndex(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.LastIndex(s, char)
+
 	return s[0:i]
 }
 
 // After create substring in source string after position when char first appear
 func After(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.Index(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.Index(s, char)
+
 	return s[i+len(char):]
 }
 
 // AfterLast create substring in source string after position when char last appear
 func AfterLast(s, char string) string {
-	if s == "" || char == "" {
+	i := strings.LastIndex(s, char)
+
+	if s == "" || char == "" || i == -1 {
 		return s
 	}
-	i := strings.LastIndex(s, char)
+
 	return s[i+len(char):]
 }
 
@@ -522,3 +530,14 @@ func RemoveWhiteSpace(str string, repalceAll bool) string {
 
 	return strings.TrimSpace(str)
 }
+
+// SubInBetween return substring between the start and end position(excluded) of source string.
+func SubInBetween(str string, start string, end string) string {
+	if _, after, ok := strings.Cut(str, start); ok {
+		if before, _, ok := strings.Cut(after, end); ok {
+			return before
+		}
+	}
+
+	return ""
+}
diff --git a/strutil/string_test.go b/strutil/string_test.go
index 209f1b9..1492d10 100644
--- a/strutil/string_test.go
+++ b/strutil/string_test.go
@@ -207,6 +207,7 @@ func TestBefore(t *testing.T) {
 	assert := internal.NewAssert(t, "TestBefore")
 
 	assert.Equal("lancet", Before("lancet", ""))
+	assert.Equal("lancet", Before("lancet", "abcdef"))
 	assert.Equal("github.com", Before("github.com/test/lancet", "/"))
 	assert.Equal("github.com/", Before("github.com/test/lancet", "test"))
 }
@@ -215,6 +216,7 @@ func TestBeforeLast(t *testing.T) {
 	assert := internal.NewAssert(t, "TestBeforeLast")
 
 	assert.Equal("lancet", BeforeLast("lancet", ""))
+	assert.Equal("lancet", BeforeLast("lancet", "abcdef"))
 	assert.Equal("github.com/test", BeforeLast("github.com/test/lancet", "/"))
 	assert.Equal("github.com/test/", BeforeLast("github.com/test/test/lancet", "test"))
 
@@ -225,6 +227,7 @@ func TestAfter(t *testing.T) {
 	assert := internal.NewAssert(t, "TestAfter")
 
 	assert.Equal("lancet", After("lancet", ""))
+	assert.Equal("lancet", After("lancet", "abcdef"))
 	assert.Equal("test/lancet", After("github.com/test/lancet", "/"))
 	assert.Equal("/lancet", After("github.com/test/lancet", "test"))
 }
@@ -233,6 +236,7 @@ func TestAfterLast(t *testing.T) {
 	assert := internal.NewAssert(t, "TestAfterLast")
 
 	assert.Equal("lancet", AfterLast("lancet", ""))
+	assert.Equal("lancet", AfterLast("lancet", "abcdef"))
 	assert.Equal("lancet", AfterLast("github.com/test/lancet", "/"))
 	assert.Equal("/lancet", AfterLast("github.com/test/lancet", "test"))
 	assert.Equal("/lancet", AfterLast("github.com/test/test/lancet", "test"))
@@ -465,3 +469,15 @@ func TestRemoveWhiteSpace(t *testing.T) {
 	assert.Equal("helloworld", RemoveWhiteSpace(str, true))
 	assert.Equal("hello world", RemoveWhiteSpace(str, false))
 }
+
+func TestSubInBetween(t *testing.T) {
+	assert := internal.NewAssert(t, "TestSubInBetween")
+
+	str := "abcde"
+
+	assert.Equal("", SubInBetween(str, "", ""))
+	assert.Equal("ab", SubInBetween(str, "", "c"))
+	assert.Equal("bc", SubInBetween(str, "a", "d"))
+	assert.Equal("", SubInBetween(str, "a", ""))
+	assert.Equal("", SubInBetween(str, "a", "f"))
+}