diff --git a/app/models/anns_cache.rb b/app/models/anns_cache.rb
index 881ca02..7952c4e 100644
--- a/app/models/anns_cache.rb
+++ b/app/models/anns_cache.rb
@@ -1,6 +1,6 @@
 class AnnsCache
   include Mongoid::Document
   field :parent_id
-	field :filter_result,type: Array,default: []
+	field :filter_result
   field :locale,type: String,default: 'zh_tw'
 end
\ No newline at end of file