diff --git a/src/models/content/Puzzle.ts b/src/models/content/Puzzle.ts
index de93758..ba7b89d 100644
--- a/src/models/content/Puzzle.ts
+++ b/src/models/content/Puzzle.ts
@@ -73,7 +73,11 @@ class PuzzleClass extends BaseModule {
       opt.quality = quality
     }
     if (dp != undefined) {
-      opt.dp = dp
+      if (dp == 'none') {
+        opt.dp = {$exists: false}
+      } else {
+        opt.dp = dp
+      }
     }
     if (timeBegin && !timeEnd) {
       opt.createtime = {$gte: timeBegin};