In order to meet the demand of high rate of GEO Satellite in GPS SBAS system, the design about navigation message format introduces the features of channel coding, distributed frame and hidden frame. For the SBAS L1 navigation message format, the traditional character matching method faces the shortcomings of large data bit demand and low recognition rate. The paper proposes a frame-head search method based on CRC check, which requires less 260 bits data and less 1.04 seconds time, and realize the frame synchronization quickly and accurately.