diff --git a/miner/miner.go b/miner/miner.go
index 7f73f3ee87..535fd5e615 100644
--- a/miner/miner.go
+++ b/miner/miner.go
@@ -135,5 +135,6 @@ func (self *Miner) PendingState() *state.StateDB {
 }
 
 func (self *Miner) PendingBlock() *types.Block {
-	return self.worker.pendingBlock()
+	copy := *self.worker.pendingBlock()
+	return &copy
 }