diff --git a/ios/sdk/WeexSDK/Sources/Module/WXDomModule.m b/ios/sdk/WeexSDK/Sources/Module/WXDomModule.m
index f65f61a376..dd4c51e2c8 100644
--- a/ios/sdk/WeexSDK/Sources/Module/WXDomModule.m
+++ b/ios/sdk/WeexSDK/Sources/Module/WXDomModule.m
@@ -211,6 +211,13 @@ - (void)addRule:(NSString*)type rule:(NSDictionary *)rule {
 }
 
 - (void)getComponentRect:(NSString*)ref callback:(WXModuleKeepAliveCallback)callback {
+    if (ref == nil || ![ref isKindOfClass:[NSString class]]) {
+        if (callback) {
+            callback(@{@"result": @(NO), @"errMsg": @"Illegal parameter, ref must be a string."}, false);
+        }
+        return;
+    }
+    
     [self performBlockOnComponentManager:^(WXComponentManager * manager) {
         if ([ref isEqualToString:@"viewport"]) {
             dispatch_async(dispatch_get_main_queue(), ^{