diff --git a/nonrepeating.go b/nonrepeating.go
new file mode 100644
index 0000000000000000000000000000000000000000..f782d4d8a5dc5a4a831a7ef0ecd22d7bde960616
--- /dev/null
+++ b/nonrepeating.go
@@ -0,0 +1,31 @@
+package main
+
+import "fmt"
+
+func lengthOfNonRepeatingSubStr(s string) int {
+	lastOccurrend := make(map[rune]int)
+	start := 0
+	maxLength := 0
+	// for i ,ch := range[]byte(s){   byte 修改rune 支持中文件
+	for i, ch := range []rune(s) {
+		if lastI, ok := lastOccurrend[ch]; ok && lastI >= start {
+			start = lastOccurrend[ch] + 1
+		}
+		if i-start+1 > maxLength {
+			maxLength = i - start + 1
+		}
+		lastOccurrend[ch] = i
+
+	}
+	for v, _ := range lastOccurrend {
+		fmt.Printf("(%c )", v)
+	}
+	fmt.Println()
+
+	return maxLength
+}
+
+func main() {
+	fmt.Println(lengthOfNonRepeatingSubStr("dafwefwefwfsdfsdf"))
+	fmt.Println(lengthOfNonRepeatingSubStr("我家你中国，我在家乡"))
+}