Abstract: In order to get the optimal wavelength pairs for twocolor satellite laser ranging,with the factors including atmosphere effect,the response of the receiver and the laser considered,beginning with the precision of atmosphere correction,based on the lidar equation,the wavelength figure of merit,which can determine whether the pair is selected properly,is obtained.Various figure of merits of the wavelength pairs induced by the technology of harmony and Raman scattering is calculated,the possible wavelength pairs are discussed.Finally the standard and basis for the selection of optimal wavelengths is set up.