diff --git a/consensus/XDPoS/engines/engine_v2/engine.go b/consensus/XDPoS/engines/engine_v2/engine.go
index c947df1fcc..b1a7712f1b 100644
--- a/consensus/XDPoS/engines/engine_v2/engine.go
+++ b/consensus/XDPoS/engines/engine_v2/engine.go
@@ -35,7 +35,7 @@ type XDPoS_v2 struct {
 	currentRound      utils.Round
 	highestVotedRound utils.Round
 	highestQuorumCert *utils.QuorumCert
-	// LockQC in XDPoS Consensus 2.0, used in voting rule
+	// lockQuorumCert in XDPoS Consensus 2.0, used in voting rule
 	lockQuorumCert     *utils.QuorumCert
 	highestTimeoutCert *utils.TimeoutCert
 	highestCommitBlock *utils.BlockInfo
@@ -79,6 +79,8 @@ func (x *XDPoS_v2) SetNewRoundFaker(newRound utils.Round, resetTimer bool) {
 
 // Utils for test to check currentRound value
 func (x *XDPoS_v2) GetCurrentRound() utils.Round {
+	x.lock.Lock()
+	defer x.lock.Unlock()
 	return x.currentRound
 }
 
@@ -307,22 +309,27 @@ func (x *XDPoS_v2) verifyTC(timeoutCert *utils.TimeoutCert) error {
 	return nil
 }
 
-// Update local QC variables including highestQC & lockQC, as well as update commit blockInfo before call
-/*
-	1. Update HighestQC and LockQC
-	2. Update commit block info (TODO)
-	3. Check QC round >= node's currentRound. If yes, call setNewRound
-*/
-func (x *XDPoS_v2) processQC(quorumCert *utils.QuorumCert) error {
+// Update local QC variables including highestQC & lockQuorumCert, as well as update commit blockInfo before call
+func (x *XDPoS_v2) processQC(blockCahinReader consensus.ChainReader, quorumCert *utils.QuorumCert) error {
+	// 1. Update HighestQC
 	if x.highestQuorumCert == nil || quorumCert.ProposedBlockInfo.Round > x.highestQuorumCert.ProposedBlockInfo.Round {
-		x.highestQuorumCert = quorumCert
 		//TODO: do I need a clone?
+		x.highestQuorumCert = quorumCert
 	}
-	//TODO: x.blockchain.getBlock(quorumCert.ProposedBlockInfo.Hash) then get the QC inside that block header
-	//TODO: update lockQC
+	// 2. Get QC from header and update lockQuorumCert
+	proposedBlockHeader := blockCahinReader.GetHeaderByHash(quorumCert.ProposedBlockInfo.Hash)
+	var decodedExtraField utils.ExtraFields_v2
+	utils.DecodeBytesExtraFields(proposedBlockHeader.Extra, &decodedExtraField)
+	x.lockQuorumCert = &decodedExtraField.QuorumCert
+
+	// 3. Update commit block info
 	//TODO: find parent and grandparent and grandgrandparent block, check round number, if so, commit grandgrandparent
+
 	if quorumCert.ProposedBlockInfo.Round >= x.currentRound {
-		x.setNewRound(quorumCert.ProposedBlockInfo.Round + 1)
+		err := x.setNewRound(quorumCert.ProposedBlockInfo.Round + 1)
+		if err != nil {
+			return err
+		}
 	}
 	return nil
 }
@@ -364,8 +371,8 @@ func (x *XDPoS_v2) verifyVotingRule(header *types.Header) error {
 		Make sure this node has not voted for this round. We can have a variable highestVotedRound, and check currentRound > highestVotedRound.
 		HotStuff Voting rule:
 		header's round == local current round, AND (one of the following two:)
-		header's block extends LockQC's ProposedBlockInfo (we need a isExtending(block_a, block_b) function), OR
-		header's QC's ProposedBlockInfo.Round > LockQC's ProposedBlockInfo.Round
+		header's block extends lockQuorumCert's ProposedBlockInfo (we need a isExtending(block_a, block_b) function), OR
+		header's QC's ProposedBlockInfo.Round > lockQuorumCert's ProposedBlockInfo.Round
 	*/
 	return nil
 }
diff --git a/eth/bfter/bft.go b/eth/bfter/bft.go
index 54b0517cc5..faeaa48cbe 100644
--- a/eth/bfter/bft.go
+++ b/eth/bfter/bft.go
@@ -4,6 +4,7 @@ import (
 	"github.com/XinFinOrg/XDPoSChain/consensus"
 	"github.com/XinFinOrg/XDPoSChain/consensus/XDPoS"
 	"github.com/XinFinOrg/XDPoSChain/consensus/XDPoS/utils"
+	"github.com/XinFinOrg/XDPoSChain/core"
 	"github.com/XinFinOrg/XDPoSChain/log"
 	lru "github.com/hashicorp/golang-lru"
 )
@@ -18,10 +19,11 @@ type broadcastTimeoutFn func(*utils.Timeout)
 type broadcastSyncInfoFn func(*utils.SyncInfo)
 
 type Bfter struct {
-	broadcastCh chan interface{}
-	quit        chan struct{}
-	consensus   ConsensusFns
-	broadcast   BroadcastFns
+	blockCahinReader *core.BlockChain
+	broadcastCh      chan interface{}
+	quit             chan struct{}
+	consensus        ConsensusFns
+	broadcast        BroadcastFns
 
 	// Message Cache
 	knownVotes     *lru.ARCCache
@@ -46,17 +48,18 @@ type BroadcastFns struct {
 	SyncInfo broadcastSyncInfoFn
 }
 
-func New(broadcasts BroadcastFns) *Bfter {
+func New(broadcasts BroadcastFns, blockCahinReader *core.BlockChain) *Bfter {
 	knownVotes, _ := lru.NewARC(messageLimit)
 	knownSyncInfos, _ := lru.NewARC(messageLimit)
 	knownTimeouts, _ := lru.NewARC(messageLimit)
 	return &Bfter{
-		quit:           make(chan struct{}),
-		broadcastCh:    make(chan interface{}),
-		broadcast:      broadcasts,
-		knownVotes:     knownVotes,
-		knownSyncInfos: knownSyncInfos,
-		knownTimeouts:  knownTimeouts,
+		quit:             make(chan struct{}),
+		broadcastCh:      make(chan interface{}),
+		broadcast:        broadcasts,
+		knownVotes:       knownVotes,
+		knownSyncInfos:   knownSyncInfos,
+		knownTimeouts:    knownTimeouts,
+		blockCahinReader: blockCahinReader,
 	}
 }
 
diff --git a/eth/handler.go b/eth/handler.go
index 07576519fd..43e385dda0 100644
--- a/eth/handler.go
+++ b/eth/handler.go
@@ -227,7 +227,7 @@ func NewProtocolManager(config *params.ChainConfig, mode downloader.SyncMode, ne
 		Timeout:  manager.BroadcastTimeout,
 		SyncInfo: manager.BroadcastSyncInfo,
 	}
-	manager.bfter = bfter.New(broadcasts)
+	manager.bfter = bfter.New(broadcasts, blockchain)
 	if blockchain.Config().XDPoS != nil {
 		manager.bfter.SetConsensusFuns(engine)
 	}