Abstract: In this paper, based on the vehicle Doppler lidar, the range and velocity measurement at 1 550 nm are studied, and the vehicle lidar and range synchronous measurement values are set. The Doppler frequency of heterodyne signal is calculated by Fourier nalysis method, so as to calculate the target velocity. A modulation scheme to improve the bandwidth of the transmitted signal is proposed to measure the target distance and solve the contradiction between the maximum measurement range and the range resolution. y analyzing the cause of the influence, the pseudo periodic code is inserted into the pseudo-random code modulation code, and the laser flight time and the Doppler frequency of the heterodyne signal are calculated by using the relevant functions at the receiving end. The simulation results show that pulse and amplitude modulation are beneficial to improve the sensitivity of the vehicle borne lidar. The periodic code is inserted into the pseudo-random code, and the synchronous measurement of speed and distance can be realized. The width of modulation code determines the accuracy of distance measurement, and the length of transmitted signal determines the accuracy of speed measurement.