diff --git a/tutorials/source_zh_cn/generative/pix2pix.ipynb b/tutorials/source_zh_cn/generative/pix2pix.ipynb
index 9c318ddc0be8c290eeb6a2a7e0579e946832d025..2310fa9e4d51d094d5117c60f94f9521185f18e1 100644
--- a/tutorials/source_zh_cn/generative/pix2pix.ipynb
+++ b/tutorials/source_zh_cn/generative/pix2pix.ipynb
@@ -469,7 +469,7 @@
     "def forword_dis(reala, realb):\n",
     "    lambda_dis = 0.5\n",
     "    fakeb = net_generator(reala)\n",
-    "    pred0 = net_discriminator(reala, fakeb)\n",
+    "    pred0 = net_discriminator(reala, ops.stop_gradient(fakeb))\n",
     "    pred1 = net_discriminator(reala, realb)\n",
     "    loss_d = loss_f(pred1, ops.ones_like(pred1)) + loss_f(pred0, ops.zeros_like(pred0))\n",
     "    loss_dis = loss_d * lambda_dis\n",