Abstract: Based on the working principle and measurement peculiarity of laser velocimeter and the working peculiarity of inertial navigation system(INS), an integrated navigation method was proposed which could be used to realize autonomous high-accuracy positioning and orientation of land vehicles. The error model of the three-beam laser velocimeter used in vehicle positioning and orientation was deduced which was combined with error model of strapdown inertial navigation system(SINS). Kalman filter states of integrated navigation were chosen, and measurement model was deduced. At last, simulation of the SINS/laser velocimeter integrated positioning and orientation method was carried out, and the correlated results were presented, by which the method proposed in this paper was validated.