diff --git a/server/light_backtask/task/chain_activity.go b/server/light_backtask/task/chain_activity.go
index c0125e5e..64b83f3c 100644
--- a/server/light_backtask/task/chain_activity.go
+++ b/server/light_backtask/task/chain_activity.go
@@ -152,8 +152,13 @@ func (this* chainActivity) saveToDb(ds *f5.DataSet) bool {
 				tokenId := q5.SafeToString(nft[0])
 				to := q5.SafeToString(nft[1])
 				var isMint int32
-				if nft[2].(bool) {
-					isMint = 1
+				if value, ok := nft[2].(bool); ok {
+					if value {
+						isMint = 1
+					}
+				} else {
+					decodeJsonOk = false
+					break
 				}
 				var dbErr error
 				f5.GetGoStyleDb().Upsert(