diff --git a/cmd/tomo/config.go b/cmd/tomo/config.go
index 6fc12571e7..51d6bf8869 100644
--- a/cmd/tomo/config.go
+++ b/cmd/tomo/config.go
@@ -36,6 +36,7 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 	whisper "github.com/ethereum/go-ethereum/whisper/whisperv6"
 	"github.com/naoina/toml"
+	"github.com/ethereum/go-ethereum/common"
 )
 
 var (
@@ -151,6 +152,11 @@ func makeConfigNode(ctx *cli.Context) (*node.Node, tomoConfig) {
 		ctx.Set(utils.NATFlag.Name, cfg.NAT)
 	}
 
+	// Check testnet is enable.
+	if ctx.GlobalBool(utils.TomoTestnetFlag.Name) {
+		common.IsTestnet = true
+	}
+
 	// read passwords from environment
 	passwords := []string{}
 	for _, env := range cfg.Account.Passwords {
diff --git a/cmd/tomo/main.go b/cmd/tomo/main.go
index 9a125d0485..751c4babf0 100644
--- a/cmd/tomo/main.go
+++ b/cmd/tomo/main.go
@@ -109,6 +109,7 @@ var (
 		//utils.TestnetFlag,
 		//utils.RinkebyFlag,
 		//utils.VMEnableDebugFlag,
+		utils.TomoTestnetFlag,
 		utils.NetworkIdFlag,
 		utils.RPCCORSDomainFlag,
 		utils.RPCVirtualHostsFlag,
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index f158819e42..a33380d9ff 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -139,6 +139,10 @@ var (
 		Name:  "testnet",
 		Usage: "Ropsten network: pre-configured proof-of-work test network",
 	}
+	TomoTestnetFlag = cli.BoolFlag{
+		Name:  "tomo-testnet",
+		Usage: "Tomo test network",
+	}
 	RinkebyFlag = cli.BoolFlag{
 		Name:  "rinkeby",
 		Usage: "Rinkeby network: pre-configured proof-of-authority test network",
diff --git a/common/constants.go b/common/constants.go
index 0571a8cf11..89ded09a84 100644
--- a/common/constants.go
+++ b/common/constants.go
@@ -16,3 +16,5 @@ const (
 	LimitThresholdNonceInQueue = 10
 	MinGasPrice                = 2500
 )
+
+var IsTestnet bool = false
diff --git a/consensus/posv/posv.go b/consensus/posv/posv.go
index 66daca10a6..3bf49e95ae 100644
--- a/consensus/posv/posv.go
+++ b/consensus/posv/posv.go
@@ -45,8 +45,8 @@ import (
 )
 
 const (
-	inmemorySnapshots  = 128                    // Number of recent vote snapshots to keep in memory
-	M2ByteLength       = 4
+	inmemorySnapshots = 128 // Number of recent vote snapshots to keep in memory
+	M2ByteLength      = 4
 )
 
 type Masternode struct {
@@ -476,7 +476,11 @@ func whoIsCreator(snap *Snapshot, header *types.Header) (common.Address, error)
 
 func (c *Posv) YourTurn(chain consensus.ChainReader, parent *types.Header, signer common.Address) (int, int, int, bool, error) {
 	masternodes := c.GetMasternodes(chain, parent)
-	masternodes = masternodes[:len(masternodes)/2+1]
+	if common.IsTestnet {
+		// Only three mns for tomo testnet.
+		masternodes = masternodes[:3]
+	}
+	log.Error("masternodes", "masternodes", len(masternodes))
 	snap, err := c.GetSnapshot(chain, parent)
 	if err != nil {
 		log.Warn("Failed when trying to commit new work", "err", err)