diff --git a/kernel/model/flashcard.go b/kernel/model/flashcard.go
index 2cea61fa7..481e4f2f8 100644
--- a/kernel/model/flashcard.go
+++ b/kernel/model/flashcard.go
@@ -70,7 +70,7 @@ func GetTreeFlashcards(rootID string, page int) (blocks []*Block, total, pageCou
 	treeBlockIDs := map[string]bool{}
 	for _, t := range trees {
 		ast.Walk(t.Root, func(n *ast.Node, entering bool) ast.WalkStatus {
-			if !entering || !n.IsBlock() {
+			if !entering || !n.IsBlock() || ast.NodeDocument == n.Type {
 				return ast.WalkContinue
 			}