Abstract: The choice of station-s address, interval and number of stations in ground station-s space diversity technology is investigated by modeling optical link for satellite-to-ground optical communication. The result of research shows, reasonable choice of station-s address can improve the availability of satellite-toground optical communication link; the interval of stations should ensure the weathers at different stations are uncorrelated but not too long; the attenuation resulted from zenith angle is more than 10 dB when the ratio of interval and altitude of satellite is larger than 1; the necessary amount of stations is smaller if the availability of single ground station is higher; only 3 stations are needed with equivalent availability of microwave link when the availability of single station is 0.6.