diff --git a/Makefile b/Makefile
index 3d6a3e2e..357a3c4d 100644
--- a/Makefile
+++ b/Makefile
@@ -61,9 +61,19 @@ vet: ## Run go vet against code.
 	go vet ./...
 
 .PHONY: test
-test: manifests generate fmt vet envtest ## Run tests.
+test: manifests generate fmt vet envtest interpreter-test ## Run tests.
 	KUBEBUILDER_ASSETS="$(shell $(ENVTEST) use $(ENVTEST_K8S_VERSION) --bin-dir $(LOCALBIN) -p path)" go test $$(go list ./... | grep -v /e2e) -coverprofile cover.out
 
+.PHONY: interpreter-test
+interpreter-test: karmadactl ## Validate Karmada resource interpreter customizations.
+	$(KARMADACTL) interpret -f config/components/federation/workloaddeployment-interpreter.yaml --check
+	@out="$$($(KARMADACTL) interpret -f config/components/federation/workloaddeployment-interpreter.yaml --operation retain --desired-file test/interpreter/workloaddeployment-retain-desired.yaml --observed-file test/interpreter/workloaddeployment-retain-observed.yaml)"; \
+	if ! grep -q "replicas: 5" <<<"$$out"; then \
+	  printf '%s\n' "$$out"; \
+	  printf '%s\n' "expected retained WorkloadDeployment replicas to be 5"; \
+	  exit 1; \
+	fi
+
 # TODO(user): To use a different vendor for e2e tests, modify the setup under 'tests/e2e'.
 # The default setup assumes Kind is pre-installed and builds/loads the Manager Docker image locally.
 # Prometheus and CertManager are installed by default; skip with:
@@ -169,6 +179,7 @@ KUSTOMIZE ?= $(LOCALBIN)/kustomize
 CONTROLLER_GEN ?= $(LOCALBIN)/controller-gen
 DEFAULTER_GEN ?= $(LOCALBIN)/defaulter-gen
 ENVTEST ?= $(LOCALBIN)/setup-envtest
+KARMADACTL ?= $(LOCALBIN)/karmadactl
 GOLANGCI_LINT = $(LOCALBIN)/golangci-lint
 CRDOC ?= $(LOCALBIN)/crdoc
 
@@ -177,6 +188,7 @@ KUSTOMIZE_VERSION ?= v5.5.0
 CONTROLLER_TOOLS_VERSION ?= v0.16.4
 DEFAULTER_GEN_VERSION ?= v0.32.3
 ENVTEST_VERSION ?= release-0.19
+KARMADA_VERSION ?= v1.18.1
 GOLANGCI_LINT_VERSION ?= v2.12.2
 
 # renovate: datasource=go depName=fybrik.io/crdoc
@@ -202,6 +214,11 @@ envtest: $(ENVTEST) ## Download setup-envtest locally if necessary.
 $(ENVTEST): $(LOCALBIN)
 	$(call go-install-tool,$(ENVTEST),sigs.k8s.io/controller-runtime/tools/setup-envtest,$(ENVTEST_VERSION))
 
+.PHONY: karmadactl
+karmadactl: $(KARMADACTL) ## Download karmadactl locally if necessary.
+$(KARMADACTL): $(LOCALBIN)
+	$(call go-install-tool,$(KARMADACTL),github.com/karmada-io/karmada/cmd/karmadactl,$(KARMADA_VERSION))
+
 .PHONY: golangci-lint
 golangci-lint: $(GOLANGCI_LINT) ## Download golangci-lint locally if necessary.
 $(GOLANGCI_LINT): $(LOCALBIN)
diff --git a/config/components/federation/workloaddeployment-interpreter.yaml b/config/components/federation/workloaddeployment-interpreter.yaml
index 2743a63b..7a0b6fcd 100644
--- a/config/components/federation/workloaddeployment-interpreter.yaml
+++ b/config/components/federation/workloaddeployment-interpreter.yaml
@@ -7,6 +7,18 @@ spec:
     apiVersion: compute.datumapis.com/v1alpha
     kind: WorkloadDeployment
   customizations:
+    retention:
+      luaScript: |
+        function Retain(desiredObj, observedObj)
+          if observedObj.spec == nil or observedObj.spec.replicas == nil then
+            return desiredObj
+          end
+          if desiredObj.spec == nil then
+            desiredObj.spec = {}
+          end
+          desiredObj.spec.replicas = observedObj.spec.replicas
+          return desiredObj
+        end
     statusReflection:
       luaScript: |
         function ReflectStatus(observedObj)
diff --git a/test/interpreter/workloaddeployment-retain-desired.yaml b/test/interpreter/workloaddeployment-retain-desired.yaml
new file mode 100644
index 00000000..73c75383
--- /dev/null
+++ b/test/interpreter/workloaddeployment-retain-desired.yaml
@@ -0,0 +1,14 @@
+apiVersion: compute.datumapis.com/v1alpha
+kind: WorkloadDeployment
+metadata:
+  name: test-wd
+  namespace: default
+spec:
+  workloadRef:
+    name: test
+  placementName: default
+  cityCode: DFW
+  template: {}
+  scaleSettings:
+    minReplicas: 1
+  replicas: 1
diff --git a/test/interpreter/workloaddeployment-retain-observed.yaml b/test/interpreter/workloaddeployment-retain-observed.yaml
new file mode 100644
index 00000000..f1f2d36b
--- /dev/null
+++ b/test/interpreter/workloaddeployment-retain-observed.yaml
@@ -0,0 +1,14 @@
+apiVersion: compute.datumapis.com/v1alpha
+kind: WorkloadDeployment
+metadata:
+  name: test-wd
+  namespace: default
+spec:
+  workloadRef:
+    name: test
+  placementName: default
+  cityCode: DFW
+  template: {}
+  scaleSettings:
+    minReplicas: 1
+  replicas: 5