diff --git a/app/src/main/assets/updateLog.md b/app/src/main/assets/updateLog.md
index e3557a5fc..9d29de491 100644
--- a/app/src/main/assets/updateLog.md
+++ b/app/src/main/assets/updateLog.md
@@ -11,6 +11,10 @@
 * 正文出现缺字漏字、内容缺失、排版错乱等情况，有可能是净化规则或简繁转换出现问题。
 * 漫画源看书显示乱码，**阅读与其他软件的源并不通用**，请导入阅读的支持的漫画源！
 
+**2022/02/26**
+
+* 自动备份检测到webDav已有备份时不会重复备份
+
 **2022/02/25**
 
 * 修复排版导入不能导入背景图片的bug
diff --git a/app/src/main/java/io/legado/app/help/storage/Backup.kt b/app/src/main/java/io/legado/app/help/storage/Backup.kt
index 2979a0c31..b8e649fe6 100644
--- a/app/src/main/java/io/legado/app/help/storage/Backup.kt
+++ b/app/src/main/java/io/legado/app/help/storage/Backup.kt
@@ -52,7 +52,9 @@ object Backup : BackupRestore() {
         if (lastBackup + TimeUnit.DAYS.toMillis(1) < System.currentTimeMillis()) {
             Coroutine.async {
                 if (!AppWebDav.hasBackUp()) {
-                    backup(context, context.getPrefString(PreferKey.backupPath) ?: "", true)
+                    backup(context, context.getPrefString(PreferKey.backupPath), true)
+                } else {
+                    context.putPrefLong(PreferKey.lastBackup, System.currentTimeMillis())
                 }
             }.onError {
                 AppLog.put("备份出错\n${it.localizedMessage}", it)
@@ -61,7 +63,7 @@ object Backup : BackupRestore() {
         }
     }
 
-    suspend fun backup(context: Context, path: String, isAuto: Boolean = false) {
+    suspend fun backup(context: Context, path: String?, isAuto: Boolean = false) {
         context.putPrefLong(PreferKey.lastBackup, System.currentTimeMillis())
         withContext(IO) {
             FileUtils.deleteFile(backupPath)
@@ -105,12 +107,14 @@ object Backup : BackupRestore() {
                 edit.commit()
             }
             AppWebDav.backUpWebDav(backupPath)
-            if (path.isContentScheme()) {
-                copyBackup(context, Uri.parse(path), isAuto)
-            } else {
-                if (path.isEmpty()) {
+            when {
+                path.isNullOrBlank() -> {
                     copyBackup(context.getExternalFilesDir(null)!!, false)
-                } else {
+                }
+                path.isContentScheme() -> {
+                    copyBackup(context, Uri.parse(path), isAuto)
+                }
+                else -> {
                     copyBackup(File(path), isAuto)
                 }
             }