Abstract: Based on double-edge technique, the optimization of the operation parameters of Fabry-Perot interferometers in the direct detection Doppler wind lidar is presented. The effects of the laser spectral width, mirror surface defects, parallelism errors, beam divergence of illumination on the transmittance of the etalon are considered. By convolution method, the Fabry-Perot interferometer transmittance function with different spectral broadening defect is given. The free spectrum range is chosen to subtract the Rayleigh signal from the atmospheric back-scattering correctly. The transmittance of aerosol back-scatter signal through the interferometer is expressed as a function of the reflectance finesse, which is the unique system parameter. By considering the ratio of the measurement uncertainty