We have studied the anodization behavior of an Al film electrodeposited on the 316L stainless steel (316L SS) substrate and demonstrated an effective approach to fabricate the micro-cavities on the conducting substrate through anodic aluminum oxide (AAO) template. The morphologies and composition of the electroplating aluminum layers and the micro-cavities were evaluated by SEM and energy dispersive X-ray analysis (EDXA) respectively. The results indicated that different shapes of cavities with size ranging from 0.6 to 2 mm were come into being directly on 316L SS substrates. The size of cavities could be controlled by adjusting the anodizing voltage and time. And the morphologies of the initial aluminum films were found to be critical factors for successfully anodizing the Al film on 316L SS surface.