In order to meet the future demands for the complicated navigation positioning system and to solve the interference problems, we can use pseudo satellite to expand its range. A design method which can realize the baseband of GPS pseudo satellite based on FPGA is presented in this paper. First of all, the functional modules of FPGA are designed and simulated, and then the design of hardware circuit and PCB layout are completed. Finally, baseband signal of GPS pseudo satellite are validated. The test results show that the design meets the relevant requirements and achieves the desired effect.