diff --git a/database/db.go b/database/db.go
index 0646454..ee3ece2 100644
--- a/database/db.go
+++ b/database/db.go
@@ -217,3 +217,36 @@ func CheckUserPasswd(username string, password string) bool {
 		return false
 	}
 }
+
+func GetFileLinkID(md5in string) string {
+	db, err := sql.Open("sqlite3", "./data/database.db")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	// SQL语句
+	SQL := `
+	SELECT * FROM "mytable" WHERE md5 = ?
+	`
+
+	row := db.QueryRow(SQL,md5in)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// 扫描查询结果
+	var md5 string
+	var linkID string
+	var ext string
+	err = row.Scan(&linkID,&md5,&ext)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return ""
+		} else {
+			log.Fatal(err)
+		}
+		return ""
+	}
+	return linkID
+}
\ No newline at end of file
diff --git a/main.go b/main.go
index 829fce0..f6db6c9 100644
--- a/main.go
+++ b/main.go
@@ -130,6 +130,12 @@ func upload(w http.ResponseWriter, r *http.Request) {
 		}
 		md5sum := fmt.Sprintf("%x", h.Sum(nil))
 
+		oldLinkID := database.GetFileLinkID(md5sum)
+		if oldLinkID != "" {
+			w.Write([]byte(oldLinkID))
+			return
+		}
+
 		// 获取文件扩展名
 		fname := handler.Filename
 		ext := path.Ext(fname)