Abstract: This paper, by analyzing the basic principles of AES algorithm, integrating AES-128, AES-l92, AES-256 into a single design, which effectively uses the public modules and greatly reduces the chip's area compared with a single implementation of these modules respectively. In this paper, through the analysis of the current implementation of KEY in AES algorithm, the author proposes a new circuit structure. And the result shows that the area of serial AES encryption and decryption circuit is only 31 286, a maximum operating frequency is 66MHz, which meets most data exchange rate demands of the current wireless sensor networks.