diff --git a/consensus/XDPoS/api.go b/consensus/XDPoS/api.go
index f13b645864..420f0d7d59 100644
--- a/consensus/XDPoS/api.go
+++ b/consensus/XDPoS/api.go
@@ -324,9 +324,13 @@ func (api *API) GetEpochNumbersBetween(begin, end *rpc.BlockNumber) ([]uint64, e
 	if endHeader == nil {
 		return nil, errors.New("illegal end block number")
 	}
-	if beginHeader.Number.Cmp(endHeader.Number) > 0 {
+	diff := new(big.Int).Sub(endHeader.Number, beginHeader.Number).Int64()
+	if diff < 0 {
 		return nil, errors.New("illegal begin and end block number, begin > end")
 	}
+	if diff > 50_000 {
+		return nil, errors.New("block range over limit of 50,000 blocks")
+	}
 	epochSwitchInfos, err := api.XDPoS.GetEpochSwitchInfoBetween(api.chain, beginHeader, endHeader)
 	if err != nil {
 		return nil, err