diff --git a/doc/survey/dynamic_graph.md b/doc/survey/dynamic_graph.md
index 6b80b014b1b1dc50f425e1296f70984c9e9b1cbd..d03212007a34caecaf6a884d675a75dba3a71931 100644
--- a/doc/survey/dynamic_graph.md
+++ b/doc/survey/dynamic_graph.md
@@ -30,7 +30,7 @@ x = Variable(randn(20, 1)))
 label = Variable(randint(1))
 W_1, W_2 = Variable(randn(20, 20)), Variable(randn(10, 20))
 h = matmul(W_1, x)
-pred = matmul(W_2, x)
+pred = matmul(W_2, h)
 loss = softmax(pred, label)
 loss.backward()
 ```