diff --git a/python/taichi/examples/autodiff/jacobian.py b/python/taichi/examples/autodiff/jacobian.py
index dfd479457d6ad..70e6b51b0b9b9 100644
--- a/python/taichi/examples/autodiff/jacobian.py
+++ b/python/taichi/examples/autodiff/jacobian.py
@@ -15,7 +15,7 @@
 def func():
     for j in range(N_loss):
         for i in range(N_param):
-            losses[j] = ti.sin(j / 16 * np.pi) * ti.sin(
+            losses[j] += ti.sin(j / 16 * np.pi) * ti.sin(
                 i / 16 * np.pi) * params[i]