System structure of spaceborne Doppler wind lidar is investigated. Simulation system of frequency discrimination is built based on Fizeau interferometer. The wind retrieval algorithm of Mie channel is simulated and studied. The horizontal line-of-sight (HLOS) wind error is analysed using the simulated result of the radiosonde dataset. The result shows that the wind speed of lower troposphere can be retrieved in Mie channel based on Fizeau interferometer. The average values of HLOS wind error deviation and standard deviation in lower troposphere are less than 1 m·s-1 and 2 m·s-1, respectively. Distributions of aerosol and cloud have an influence on wind error for spaceborne Doppler wind lidar, and the maximum wind deviation will increase twice.