考虑大气折射对星载激光测距的影响，研究了基于光线追迹理论的激光程差计算方法。综合利用气象探空数据和高层大气模式数据，拟合得到了全国46个典型地区的年度平均大气折射率模数高度分布廓线。据此，比较分析了光线追迹算法结果与Marini-Murray模型计算结果，给出了激光程差的全国性分布状况。最后，分析了激光程差与海拔高度和卫星高度角之间的关系。

Considering the influences of atmospheric refraction on the satellite laser ranging, an algorithm for calculating the optical path differences based on ray tracing is studied. Firstly, the annual mean atmospheric refractivity modulus height profiles of 46 typical regions in China are fitted by using meteorological sounding datum and high level model datum synthetically. Secondly, the results calculated by the Marini-Murray model and ray tracing which is based on the monthly average model and the annual mean model are compared and analyzed. Then, the national distribution of the optical path difference of satellite laser ranging is presented. Finally, the relations between the optical path difference with the height above sea level of ranging site and the elevation of satellite are numerically investigated.