diff --git a/config/rbac/controller-manager/role.yaml b/config/rbac/controller-manager/role.yaml
index dac8c0b08..4688a78d5 100644
--- a/config/rbac/controller-manager/role.yaml
+++ b/config/rbac/controller-manager/role.yaml
@@ -308,3 +308,10 @@ rules:
   - list
   - update
   - watch
+- apiGroups:
+  - apiextensions.k8s.io
+  resources:
+  - customresourcedefinitions
+  verbs:
+  - get
+  - list
\ No newline at end of file
diff --git a/pkg/controller/rayclusterreplicaset/rayclusterreplicaset_controller.go b/pkg/controller/rayclusterreplicaset/rayclusterreplicaset_controller.go
index 72cd0b88a..24d648e17 100644
--- a/pkg/controller/rayclusterreplicaset/rayclusterreplicaset_controller.go
+++ b/pkg/controller/rayclusterreplicaset/rayclusterreplicaset_controller.go
@@ -22,21 +22,22 @@ import (
 	"sync"
 	"time"
 
-	"github.com/vllm-project/aibrix/pkg/controller/util/expectation"
-	apierrors "k8s.io/apimachinery/pkg/api/errors"
-
 	rayclusterv1 "github.com/ray-project/kuberay/ray-operator/apis/ray/v1"
+	orchestrationv1alpha1 "github.com/vllm-project/aibrix/api/orchestration/v1alpha1"
 	"github.com/vllm-project/aibrix/pkg/config"
-	"k8s.io/client-go/tools/record"
-	"k8s.io/klog/v2"
-	"sigs.k8s.io/controller-runtime/pkg/manager"
-	"sigs.k8s.io/controller-runtime/pkg/reconcile"
+	"github.com/vllm-project/aibrix/pkg/controller/util/expectation"
 
-	orchestrationv1alpha1 "github.com/vllm-project/aibrix/api/orchestration/v1alpha1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/client-go/tools/record"
+	"k8s.io/klog/v2"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/manager"
+	"sigs.k8s.io/controller-runtime/pkg/reconcile"
 )
 
 var (
@@ -45,11 +46,16 @@ var (
 	controllerKind                              = orchestrationv1alpha1.GroupVersion.WithKind("RayClusterReplicaSet")
 )
 
-// Add creates a new RayClusterReplicaSet Controller and adds it to the Manager with default RBAC.
+// Add first validates that the required Ray CRD (e.g., "rayclusters.ray.io") exists in the cluster.
+// If the CRD is not found, the function fails early with an error.
+// If the CRD exists, this function creates a new RayClusterReplicaSet Controller and adds it to the Manager with default RBAC.
 // The Manager will set fields on the Controller and Start it when the Manager is Started.
 func Add(mgr manager.Manager, runtimeConfig config.RuntimeConfig) error {
-	// TODO: check crd exists or not. If not, we should fail here directly without moving forward.
-	// This is used to validate whether kuberay is installed now.
+	// Check if the CRD exists. If not, fail directly.
+	crdName := "rayclusters.ray.io"
+	if err := checkCRDExists(mgr.GetClient(), crdName); err != nil {
+		return fmt.Errorf("failed to validate CRD: %v", err)
+	}
 
 	r, err := newReconciler(mgr, runtimeConfig)
 	if err != nil {
@@ -58,6 +64,29 @@ func Add(mgr manager.Manager, runtimeConfig config.RuntimeConfig) error {
 	return add(mgr, r)
 }
 
+// checkCRDExists checks if the specified CRD exists in the cluster.
+func checkCRDExists(c client.Client, crdName string) error {
+	gvk := schema.GroupVersionKind{
+		Group:   "apiextensions.k8s.io",
+		Version: "v1",
+		Kind:    "CustomResourceDefinition",
+	}
+
+	// Create an unstructured object to represent the CRD.
+	crd := &unstructured.Unstructured{}
+	crd.SetGroupVersionKind(gvk)
+	crd.SetName(crdName)
+
+	err := c.Get(context.TODO(), client.ObjectKey{Name: crdName}, crd)
+	if err != nil {
+		if apierrors.IsNotFound(err) {
+			return fmt.Errorf("CRD %q not found. Please ensure %q is installed", crdName, crdName)
+		}
+		return fmt.Errorf("error checking CRD %q: %v", crdName, err)
+	}
+	return nil
+}
+
 // newReconciler returns a new reconcile.Reconciler
 func newReconciler(mgr manager.Manager, runtimeConfig config.RuntimeConfig) (reconcile.Reconciler, error) {
 	reconciler := &RayClusterReplicaSetReconciler{