The principles of lidar wind measurement are reviewed and compared. The method of direct detection with a Fabry-Perot interferometer for 3D wind measurement is proposed. The measurement principle is described and the performance and measurement error of a lidar system is analyzed. Then, the accuracy of the lidar based on the molecular backscattering is compared with that on aerosol backscattering. The proposed lidar system with Rayleigh backscattering is given for the 3D wind measurement.