diff --git a/bot/example_test.go b/bot/example_test.go
index c0e1529..0e9a42d 100644
--- a/bot/example_test.go
+++ b/bot/example_test.go
@@ -1,6 +1,7 @@
 package bot
 
 import (
+	"encoding/hex"
 	"github.com/Tnze/go-mc/yggdrasil"
 	"log"
 )
@@ -17,7 +18,10 @@ func ExamplePingAndList() {
 
 func ExampleClient_JoinServer_offline() {
 	c := NewClient()
-	c.Name = "Tnze" // set it's name before login.
+	c.Auth.Name = "Tnze" // set it's name before login.
+
+	id := OfflineUUID(c.Auth.Name) // optional, get uuid of offline mode game
+	c.Auth.UUID = hex.EncodeToString(id[:])
 
 	//Login
 	err := c.JoinServer("localhost", 25565)
diff --git a/bot/login.go b/bot/login.go
index 609c7d2..8469ad2 100644
--- a/bot/login.go
+++ b/bot/login.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/aes"
 	"crypto/cipher"
+	"crypto/md5"
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/sha1"
@@ -16,6 +17,7 @@ import (
 
 	"github.com/Tnze/go-mc/net/CFB8"
 	pk "github.com/Tnze/go-mc/net/packet"
+	"github.com/google/uuid"
 )
 
 // Auth includes a account
@@ -25,6 +27,20 @@ type Auth struct {
 	AsTk string
 }
 
+// OfflineUUID return the UUID from player name in offline mode
+func OfflineUUID(name string) uuid.UUID {
+	var version = 3
+	h := md5.New()
+	h.Reset()
+	h.Write([]byte("OfflinePlayer:" + name))
+	s := h.Sum(nil)
+	var uuid uuid.UUID
+	copy(uuid[:], s)
+	uuid[6] = (uuid[6] & 0x0f) | uint8((version&0xf)<<4)
+	uuid[8] = (uuid[8] & 0x3f) | 0x80 // RFC 4122 variant
+	return uuid
+}
+
 // 加密请求
 func handleEncryptionRequest(c *Client, pack pk.Packet) error {
 	//创建AES对称加密密钥
diff --git a/go.mod b/go.mod
index ef839b1..78956c1 100644
--- a/go.mod
+++ b/go.mod
@@ -4,5 +4,7 @@ go 1.12
 
 require (
 	github.com/google/uuid v1.1.1
+	github.com/kr/pretty v0.1.0 // indirect
 	github.com/satori/go.uuid v1.2.0
+	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 )
diff --git a/go.sum b/go.sum
index 8139f77..a2e4d15 100644
--- a/go.sum
+++ b/go.sum
@@ -1,4 +1,11 @@
 github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
+github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/satori/go.uuid v1.2.0 h1:0uYX9dsZ2yD7q2RtLRtPSdGDWzjeM3TbMJP9utgA0ww=
 github.com/satori/go.uuid v1.2.0/go.mod h1:dA0hQrYB0VpLJoorglMZABFdXlWrHn1NEOzdhQKdks0=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=