diff --git a/backend/services/deployment.go b/backend/services/deployment.go
index 5882ed0..30e8cdf 100644
--- a/backend/services/deployment.go
+++ b/backend/services/deployment.go
@@ -96,6 +96,11 @@ func (s *DeploymentService) Create(req *CreateDeploymentRequest) (*models.LokiDe
 	if req.RetentionDays == 0 {
 		req.RetentionDays = DefaultRetentionDays
 	}
+	// 命名空间固定为 log：平台自身(lokistack)、Loki 实例(loki)、Promtail
+	// 全部收敛在同一个 log 命名空间，未显式传值时一律兜底为 log。
+	if strings.TrimSpace(req.Namespace) == "" && req.Mode == "k8s-yaml" {
+		req.Namespace = "log"
+	}
 	// 版本兼容性预检查
 	if req.Version != "" {
 		if err := ValidateLokiVersion(req.Version); err != nil {
diff --git a/frontend/src/pages/deployments/components/DeploymentCard.tsx b/frontend/src/pages/deployments/components/DeploymentCard.tsx
index 0ccfc73..8242225 100644
--- a/frontend/src/pages/deployments/components/DeploymentCard.tsx
+++ b/frontend/src/pages/deployments/components/DeploymentCard.tsx
@@ -79,7 +79,7 @@ export const DeploymentCard = memo(function DeploymentCard({
         { label: '版本', value: d.version },
         { label: '目标', value: getTargetLabel(d) },
         ...(d.mode !== 'host-docker' ? [
-          { label: '命名空间', value: d.namespace || 'loki' },
+          { label: '命名空间', value: d.namespace || 'log' },
           { label: '副本', value: `${d.replicas} · 保留 ${d.retentionDays || 30} 天` },
         ] : [{ label: '保留', value: `${d.retentionDays || 30} 天` }]),
         { label: '存储', value: d.storageConfig?.name || '本地' },
diff --git a/frontend/src/pages/deployments/components/DeploymentFormDialog.tsx b/frontend/src/pages/deployments/components/DeploymentFormDialog.tsx
index daa9176..7faf1c9 100644
--- a/frontend/src/pages/deployments/components/DeploymentFormDialog.tsx
+++ b/frontend/src/pages/deployments/components/DeploymentFormDialog.tsx
@@ -242,7 +242,7 @@ export const DeploymentFormDialog = memo(function DeploymentFormDialog({
                     <FormItem>
                       <FormLabel>命名空间 *</FormLabel>
                       <FormControl>
-                        <Input placeholder="loki" {...field} />
+                        <Input placeholder="log" {...field} />
                       </FormControl>
                       <FormMessage />
                     </FormItem>