diff --git a/consensus/XDPoS/utils/pool.go b/consensus/XDPoS/utils/pool.go
index 9c09a8ba53..c2d177a068 100644
--- a/consensus/XDPoS/utils/pool.go
+++ b/consensus/XDPoS/utils/pool.go
@@ -10,6 +10,7 @@ type PoolObj interface {
 	Hash() common.Hash
 	PoolKey() string
 	GetSigner() common.Address
+	DeepCopy() interface{}
 }
 type Pool struct {
 	objList map[string]map[common.Hash]PoolObj
@@ -22,7 +23,17 @@ func NewPool() *Pool {
 	}
 }
 func (p *Pool) Get() map[string]map[common.Hash]PoolObj {
-	return p.objList
+	p.lock.RLock()
+	defer p.lock.RUnlock()
+	dataCopy := make(map[string]map[common.Hash]PoolObj, len(p.objList))
+	for k1, v1 := range p.objList {
+		dataCopy[k1] = make(map[common.Hash]PoolObj, len(v1))
+		for k2, v2 := range v1 {
+			dataCopy[k1][k2] = v2.DeepCopy().(PoolObj)
+		}
+	}
+
+	return dataCopy
 }
 
 func (p *Pool) Add(obj PoolObj) (int, map[common.Hash]PoolObj) {
@@ -36,10 +47,18 @@ func (p *Pool) Add(obj PoolObj) (int, map[common.Hash]PoolObj) {
 	}
 	objListKeyed[obj.Hash()] = obj
 	numOfItems := len(objListKeyed)
-	return numOfItems, objListKeyed
+
+	dataCopy := make(map[common.Hash]PoolObj, len(objListKeyed))
+	for k, v := range objListKeyed {
+		dataCopy[k] = v.DeepCopy().(PoolObj)
+	}
+
+	return numOfItems, dataCopy
 }
 
 func (p *Pool) Size(obj PoolObj) int {
+	p.lock.RLock()
+	defer p.lock.RUnlock()
 	poolKey := obj.PoolKey()
 	objListKeyed, ok := p.objList[poolKey]
 	if !ok {
@@ -84,8 +103,8 @@ func (p *Pool) Clear() {
 }
 
 func (p *Pool) GetObjsByKey(poolKey string) []PoolObj {
-	p.lock.Lock()
-	defer p.lock.Unlock()
+	p.lock.RLock()
+	defer p.lock.RUnlock()
 
 	objListKeyed, ok := p.objList[poolKey]
 	if !ok {
@@ -94,8 +113,8 @@ func (p *Pool) GetObjsByKey(poolKey string) []PoolObj {
 	objList := make([]PoolObj, len(objListKeyed))
 	cnt := 0
 	for _, obj := range objListKeyed {
-		objList[cnt] = obj
-		cnt += 1
+		objList[cnt] = obj.DeepCopy().(PoolObj)
+		cnt++
 	}
 	return objList
 }
diff --git a/core/types/consensus_v2.go b/core/types/consensus_v2.go
index 2f573ca354..12f35c9b17 100644
--- a/core/types/consensus_v2.go
+++ b/core/types/consensus_v2.go
@@ -12,6 +12,12 @@ import (
 type Round uint64
 type Signature []byte
 
+func (s Signature) DeepCopy() interface{} {
+	cpy := make([]byte, len(s))
+	copy(cpy, s)
+	return s
+}
+
 // Block Info struct in XDPoS 2.0, used for vote message, etc.
 type BlockInfo struct {
 	Hash   common.Hash `json:"hash"`
@@ -27,6 +33,20 @@ type Vote struct {
 	GapNumber         uint64         `json:"gapNumber"`
 }
 
+func (v *Vote) DeepCopy() interface{} {
+	proposedBlockInfoCopy := &BlockInfo{
+		Hash:   v.ProposedBlockInfo.Hash,
+		Round:  v.ProposedBlockInfo.Round,
+		Number: new(big.Int).Set(v.ProposedBlockInfo.Number),
+	}
+	return &Vote{
+		signer:            v.signer,
+		ProposedBlockInfo: proposedBlockInfoCopy,
+		Signature:         v.Signature.DeepCopy().(Signature),
+		GapNumber:         v.GapNumber,
+	}
+}
+
 func (v *Vote) Hash() common.Hash {
 	return rlpHash(v)
 }
@@ -52,6 +72,15 @@ type Timeout struct {
 	GapNumber uint64
 }
 
+func (t *Timeout) DeepCopy() interface{} {
+	return &Timeout{
+		signer:    t.signer,
+		Round:     t.Round,
+		Signature: t.Signature.DeepCopy().(Signature),
+		GapNumber: t.GapNumber,
+	}
+}
+
 func (t *Timeout) Hash() common.Hash {
 	return rlpHash(t)
 }
@@ -75,6 +104,42 @@ type SyncInfo struct {
 	HighestTimeoutCert *TimeoutCert
 }
 
+func (s *SyncInfo) DeepCopy() interface{} {
+	var highestQCCopy *QuorumCert
+	if s.HighestQuorumCert != nil {
+		sigsCopy := make([]Signature, len(s.HighestQuorumCert.Signatures))
+		for i, sig := range s.HighestQuorumCert.Signatures {
+			sigsCopy[i] = sig.DeepCopy().(Signature)
+		}
+		highestQCCopy = &QuorumCert{
+			ProposedBlockInfo: &BlockInfo{
+				Hash:   s.HighestQuorumCert.ProposedBlockInfo.Hash,
+				Round:  s.HighestQuorumCert.ProposedBlockInfo.Round,
+				Number: new(big.Int).Set(s.HighestQuorumCert.ProposedBlockInfo.Number),
+			},
+			Signatures: sigsCopy,
+			GapNumber:  s.HighestQuorumCert.GapNumber,
+		}
+	}
+
+	var highestTimeoutCopy *TimeoutCert
+	if s.HighestTimeoutCert != nil {
+		sigsCopy := make([]Signature, len(s.HighestTimeoutCert.Signatures))
+		for i, sig := range s.HighestTimeoutCert.Signatures {
+			sigsCopy[i] = sig.DeepCopy().(Signature)
+		}
+		highestTimeoutCopy = &TimeoutCert{
+			Round:      s.HighestTimeoutCert.Round,
+			Signatures: sigsCopy,
+			GapNumber:  s.HighestTimeoutCert.GapNumber,
+		}
+	}
+	return &SyncInfo{
+		HighestQuorumCert:  highestQCCopy,
+		HighestTimeoutCert: highestTimeoutCopy,
+	}
+}
+
 func (s *SyncInfo) Hash() common.Hash {
 	return rlpHash(s)
 }