The effects of atmosphere turbulence in different heights are simulated by using multi-phase screen method.And phase screen is generated through the interpolation algorithm based on the phase covariance method.Atmospheric turbulence change with time is simulated.Optical intensity change with time is simulated under different diameters of downlink receiving antenna and different diameters of uplink Gauss beam.In addition,the received optical intensity signals are analyzed in time domain and frequency domain.