diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 682c647f0..bab9ee9b2 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -146,13 +146,13 @@ module ApplicationHelper
   # 用户图像url，如果不存在的话，source为匿名用户，即默认使用匿名用户图像
   def url_to_avatar(source)
     if File.exist?(disk_filename(source&.class, source&.id))
-      ctime = File.ctime(disk_filename(source.class, source&.id)).to_i
-      if %w(User Organization).include?(source.class.to_s)
-        File.join("images", relative_path, ["#{source.class}", "#{source&.id}"]) + "?t=#{ctime}"
+      ctime = File.ctime(disk_filename(source&.class, source&.id)).to_i
+      if %w(User Organization).include?(source&.class.to_s)
+        File.join("images", relative_path, ["#{source&.class}", "#{source&.id}"]) + "?t=#{ctime}"
       else
-        File.join("images/avatars", ["#{source.class}", "#{source&.id}"]) + "?t=#{ctime}"
+        File.join("images/avatars", ["#{source&.class}", "#{source&.id}"]) + "?t=#{ctime}"
       end
-    elsif source.class.to_s == 'User'
+    elsif source&.class.to_s == 'User'
       source.get_letter_avatar_url
     end
   end
diff --git a/app/helpers/avatar_helper.rb b/app/helpers/avatar_helper.rb
index 21cffd1be..ad0ec0cde 100644
--- a/app/helpers/avatar_helper.rb
+++ b/app/helpers/avatar_helper.rb
@@ -13,13 +13,13 @@ module AvatarHelper
 
   def url_to_avatar(source)
     if File.exist?(disk_filename(source&.class, source&.id))
-      ctime = File.ctime(disk_filename(source.class, source&.id)).to_i
-      if %w(User Organization).include?(source.class.to_s)
-        File.join("images", relative_path, ["#{source.class}", "#{source&.id}"]) + "?t=#{ctime}"
+      ctime = File.ctime(disk_filename(source&.class, source&.id)).to_i
+      if %w(User Organization).include?(source&.class.to_s)
+        File.join("images", relative_path, ["#{source&.class}", "#{source&.id}"]) + "?t=#{ctime}"
       else
-        File.join("images/avatars", ["#{source.class}", "#{source&.id}"]) + "?t=#{ctime}"
+        File.join("images/avatars", ["#{source&.class}", "#{source&.id}"]) + "?t=#{ctime}"
       end
-    elsif source.class.to_s == 'User'
+    elsif source&.class.to_s == 'User'
       source.get_letter_avatar_url
     end
   end