diff --git a/app/models/memo.rb b/app/models/memo.rb
index f6449a550..94ff5cee2 100644
--- a/app/models/memo.rb
+++ b/app/models/memo.rb
@@ -9,7 +9,7 @@ class Memo < ActiveRecord::Base
 	# 若是主题帖，则内容可以是空
 	#validates :content, presence: true, if: Proc.new{|o| !o.parent_id.nil? }
 	validates_length_of :subject, maximum: 50
-	validates_length_of :content, maximum: 40000
+	validates_length_of :content, maximum: 20000
 	validate :cannot_reply_to_locked_topic, :on => :create
 
 	acts_as_tree :counter_cache => :replies_count, :order => "#{Memo.table_name}.created_at ASC"
diff --git a/app/views/forums/show.html.erb b/app/views/forums/show.html.erb
index 3d239cff1..4bbf81668 100644
--- a/app/views/forums/show.html.erb
+++ b/app/views/forums/show.html.erb
@@ -76,8 +76,8 @@
             $("#error").html("主题 过长（最长为 50 个字符）").show();
             return false;
         }
-       if(memo_content.html().trim().length > 40000){
-            $("#error").html("内容 过长（最长为 40000 个字符）").show();
+       if(memo_content.html().trim().length > 20000){
+            $("#error").html("内容 过长（最长为 20000 个字符）").show();
            return false;
         }
         return true;