Aiming at the practical problem of magnetometer/satellite positioning system integrated measurement of vehicle attitude angle, this paper studies the method to improve the measurement accuracy according to the characteristics of different factors affecting the measurement accuracy. In this paper, the least square algorithm is used to calibrate the magnetometer to eliminate the system error, and the discrete Kalman filter algorithm is used to eliminate the influence of measurement error. The experimental results show that for the calibrated magnetometer, based on filter algorithm, the absolute mean error of the measurement is reduced from 2.366 1% to 0.592 6%, which proves that the method is effective.