diff --git a/python/paddle/v2/fluid/memory_optimization_transpiler.py b/python/paddle/v2/fluid/memory_optimization_transpiler.py
index 11e2cfb3cc5818965144e32bff80427ff4eafcef..8bb8cf7b1a5ddf44427637229bdc31ac0e151e44 100644
--- a/python/paddle/v2/fluid/memory_optimization_transpiler.py
+++ b/python/paddle/v2/fluid/memory_optimization_transpiler.py
@@ -155,6 +155,9 @@ class ControlFlowGraph(object):
                     for x in defs_can_optimize
                 ]
                 for x, x_shape in out_pair:
+                    # If x is both in uses and defs, it can not be optimized!
+                    if x in self._uses[i]:
+                        continue
                     for index, cache_pair in enumerate(self.pool):
                         cache_var = cache_pair[0]
                         cache_shape = cache_pair[1]