diff --git a/consensus/ethash/consensus.go b/consensus/ethash/consensus.go
index 1c38b80ea..b6e7b9511 100644
--- a/consensus/ethash/consensus.go
+++ b/consensus/ethash/consensus.go
@@ -31,6 +31,7 @@ import (
 	"github.com/ethereum/go-ethereum/consensus/misc"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/trie"
@@ -330,7 +331,13 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainHeaderReader, header, pa
 // the difficulty that a new block should have when created at time
 // given the parent block's time and difficulty.
 func (ethash *Ethash) CalcDifficulty(chain consensus.ChainHeaderReader, time uint64, parent *types.Header) *big.Int {
-	return CalcDifficulty(chain.Config(), time, parent)
+	var config = chain.Config()
+	var ret = CalcDifficulty(config, time, parent)
+	if nil != config.CappedMaximumDifficulty && ret.Cmp(config.CappedMaximumDifficulty) >= 0 {
+		log.Info(fmt.Sprintf("Using capped difficulty %d", config.CappedMaximumDifficulty))
+		return config.CappedMaximumDifficulty
+	}
+	return ret
 }
 
 // CalcDifficulty is the difficulty adjustment algorithm. It returns