To improve the anti-interference ability of serial communication, this paper designs and implements an asynchronous serial communication method. Communication data is encoded in the form of Differential Manchester Encoding. According to the characteristics of Differential Manchester Encoding, this paper designs a logic module to get synchronous clock and receive every bit of data transmitted Based on FPGA. This paper realizes the sending module, encoding module, decoding module and receiving module. The method given in this paper is tested and proved to be stable and feasible.