In order to meet the miniaturization, low power, low cost and increasingly high precision requires of Strapdown navigation system, the Strapdown Navigation Computer based on DSP and FPGA is researched in this paper. DSP is used to process the data. The FPGA has functions of data collected and I/O controlled etc, the dual-port RAM interface complete the data communication between DSP and FPGA. Two CPU give full play to their respective characteristics, the coordinated work, can complete the function of the navigation computer well.