Abstract: The principle of coherent wind lidar and digital filter banks were introduced briefly at first, and then the theory of cosine modulated filter banks was analyzed. Cosine modulated filter banks have excellent characteristics such as simple realization and less resources occupying. Signal can be decomposed into several narrow sub-band by using cosine modulated filter banks. The Doppler frequency of the target will fall into one of sub-band and the higher SNR can be obtained by processing each sub-band. Based on this method, a 8-channel cosine modulated filter banks were designed with Matlab, which was used in coherent wind lidar signal processing simulations. The results of the simulation and measured signal prove the correctness of the method.