Aiming at the problem that the complementary filtering in the integrated navigation system could not adapt to the motion state change and the magnetic field disturbance, a multi-sensor complementary filtering algorithm with variable parameters is designed.Firstly, the sensor noise is analyzed in frequency domain, and the complementary filter is designed according to the spectral characteristics.After that, the motion state and magnetic field are monitored through accelerometer and electronic compass, according which to set the filter parameters to decrease the estimation error.Finally, with FPGA as the core processor, an integrated navigation system of MEMS gyroscope, accelerometer and electronic compass is developed to verify the algorithm.The experimental results show that:Compared with the commercial AHRS, the algorithm can keep a higher system output accuracy, and reduce the influence of the motion state change and the magnetic field disturbance effectively.