diff --git a/pkg/apiserver/authentication/identityprovider/oidc/oidc.go b/pkg/apiserver/authentication/identityprovider/oidc/oidc.go
index e22717e88..88308e2cf 100644
--- a/pkg/apiserver/authentication/identityprovider/oidc/oidc.go
+++ b/pkg/apiserver/authentication/identityprovider/oidc/oidc.go
@@ -19,7 +19,6 @@ package oidc
 import (
 	"context"
 	"crypto/tls"
-	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -116,7 +115,7 @@ type oidcIdentity struct {
 }
 
 func (o oidcIdentity) GetUserID() string {
-	return base64.RawURLEncoding.EncodeToString([]byte(o.Sub))
+	return o.Sub
 }
 
 func (o oidcIdentity) GetUsername() string {
diff --git a/pkg/apiserver/authentication/identityprovider/oidc/oidc_test.go b/pkg/apiserver/authentication/identityprovider/oidc/oidc_test.go
index 20ff0175c..2f351de5f 100644
--- a/pkg/apiserver/authentication/identityprovider/oidc/oidc_test.go
+++ b/pkg/apiserver/authentication/identityprovider/oidc/oidc_test.go
@@ -198,7 +198,7 @@ var _ = Describe("OIDC", func() {
 			req := &http.Request{URL: url}
 			identity, err := provider.IdentityExchangeCallback(req)
 			Expect(err).Should(BeNil())
-			Expect(identity.GetUserID()).Should(Equal(base64.RawURLEncoding.EncodeToString([]byte("110169484474386276334"))))
+			Expect(identity.GetUserID()).Should(Equal("110169484474386276334"))
 			Expect(identity.GetUsername()).Should(Equal("test"))
 			Expect(identity.GetEmail()).Should(Equal("test@kubesphere.io"))
 		})