Abstract: The high spectral resolution lidar has the inherent characteristics of separating atmospheric molecular scattering from aerosol scattering signals, and can measure the aerosol backscattering coefficient and extinction coefficient profiles without assuming lidar ratio. However, due to the variable distribution of atmospheric aerosols in the world, the signal -to -noise ratio of the echo signals of the molecular channels and the aerosol channels is inconsistent, and eventually the inversion error becomes larger. Therefore, the transmission energy distribution of the two channels must be considered to reduce the inversion error. Based on the correlation mechanism between echo signals and aerosols distribution, the global aerosol distribution was divided into three types. The signal-to-noise ratio and the inversion error of the molecular channel and the parallel reference channel were analyzed and compared with the splitting ratio, and the optimized splitting ratio in each atmospheric mode was obtained.