diff --git a/pkg/controller/sidecarset/sidecarset_processor.go b/pkg/controller/sidecarset/sidecarset_processor.go
index da3e06c9ec..4e4cec1479 100644
--- a/pkg/controller/sidecarset/sidecarset_processor.go
+++ b/pkg/controller/sidecarset/sidecarset_processor.go
@@ -310,6 +310,9 @@ func (p *Processor) getMatchingPods(s *appsv1alpha1.SidecarSet) ([]*corev1.Pod,
 func (p *Processor) getSelectedPods(namespaces sets.String, selector labels.Selector) (relatedPods []*corev1.Pod, err error) {
 	// DisableDeepCopy:true, indicates must be deep copy before update pod objection
 	listOpts := &client.ListOptions{LabelSelector: selector}
+	if selector.String() == "" {
+		listOpts = &client.ListOptions{}
+	}
 	for _, ns := range namespaces.List() {
 		allPods := &corev1.PodList{}
 		listOpts.Namespace = ns
diff --git a/pkg/controller/sidecarset/sidecarset_processor_test.go b/pkg/controller/sidecarset/sidecarset_processor_test.go
index 8752b928d3..fc03994164 100644
--- a/pkg/controller/sidecarset/sidecarset_processor_test.go
+++ b/pkg/controller/sidecarset/sidecarset_processor_test.go
@@ -261,6 +261,16 @@ func TestScopeNamespacePods(t *testing.T) {
 	if len(pods) != 50 {
 		t.Fatalf("except matching pods count(%d), but get count(%d)", 50, len(pods))
 	}
+	sidecarSet.Spec.Selector = nil
+	pods, err = processor.getMatchingPods(sidecarSet)
+	if err != nil {
+		t.Fatalf("getMatchingPods failed: %s", err.Error())
+		return
+	}
+	if len(pods) != 50 {
+		t.Fatalf("except matching pods count(%d), but get count(%d)", 50, len(pods))
+	}
+
 }
 
 func TestCanUpgradePods(t *testing.T) {
diff --git a/pkg/webhook/sidecarset/validating/sidecarset_create_update_handler.go b/pkg/webhook/sidecarset/validating/sidecarset_create_update_handler.go
index 10611abce3..ae082d810c 100644
--- a/pkg/webhook/sidecarset/validating/sidecarset_create_update_handler.go
+++ b/pkg/webhook/sidecarset/validating/sidecarset_create_update_handler.go
@@ -115,11 +115,12 @@ func (h *SidecarSetCreateUpdateHandler) validateSidecarSetSpec(obj *appsv1alpha1
 	allErrs := field.ErrorList{}
 
 	//validate spec selector
-	if spec.Selector == nil {
-		allErrs = append(allErrs, field.Required(fldPath.Child("selector"), "no selector defined for SidecarSet"))
-	} else {
+	if spec.Selector != nil {
 		allErrs = append(allErrs, validateSelector(spec.Selector, fldPath.Child("selector"))...)
 	}
+	if spec.Selector == nil && spec.Namespace == "" && spec.NamespaceSelector == nil {
+		allErrs = append(allErrs, field.Required(fldPath.Child("selector"), "no selector defined for SidecarSet"))
+	}
 	if spec.Namespace != "" && spec.NamespaceSelector != nil {
 		allErrs = append(allErrs, field.Required(fldPath.Child("namespace, namespaceSelector"), "namespace and namespaceSelector are mutually exclusive"))
 	} else if spec.NamespaceSelector != nil {
diff --git a/test/e2e/apps/sidecarset.go b/test/e2e/apps/sidecarset.go
index 8c636d129b..aa65580ed2 100644
--- a/test/e2e/apps/sidecarset.go
+++ b/test/e2e/apps/sidecarset.go
@@ -151,6 +151,32 @@ var _ = SIGDescribe("SidecarSet", func() {
 			ginkgo.By(fmt.Sprintf("sidecarSet inject pod sidecar container done"))
 		})
 
+		framework.ConformanceIt("sidecarSet no Selector inject pod sidecar container", func() {
+			// create sidecarSet
+			sidecarSet := tester.NewBaseSidecarSet(ns)
+			sidecarSet.Spec.Selector = nil
+			ginkgo.By(fmt.Sprintf("Creating SidecarSet %s", sidecarSet.Name))
+			tester.CreateSidecarSet(sidecarSet)
+			time.Sleep(time.Second)
+
+			// create deployment
+			deployment := tester.NewBaseDeployment(ns)
+			ginkgo.By(fmt.Sprintf("Creating Deployment(%s/%s)", deployment.Namespace, deployment.Name))
+			tester.CreateDeployment(deployment)
+
+			// get pods
+			pods, err := tester.GetSelectorPods(deployment.Namespace, deployment.Spec.Selector)
+			gomega.Expect(err).NotTo(gomega.HaveOccurred())
+			pod := pods[0]
+			gomega.Expect(pod.Spec.Containers).To(gomega.HaveLen(len(deployment.Spec.Template.Spec.Containers) + len(sidecarSet.Spec.Containers)))
+			gomega.Expect(pod.Spec.InitContainers).To(gomega.HaveLen(len(deployment.Spec.Template.Spec.InitContainers) + len(sidecarSet.Spec.InitContainers)))
+			exceptContainers := []string{"nginx-sidecar", "main", "busybox-sidecar"}
+			for i, except := range exceptContainers {
+				gomega.Expect(except).To(gomega.Equal(pod.Spec.Containers[i].Name))
+			}
+			ginkgo.By(fmt.Sprintf("sidecarSet inject pod sidecar container done"))
+		})
+
 		framework.ConformanceIt("sidecarSet inject pod sidecar container volumeMounts", func() {
 			// create sidecarSet
 			sidecarSet := tester.NewBaseSidecarSet(ns)