Based on the exponentiated Weibull atmospheric turbulence model,the OFDM-FSO communication system in high altitude platform was constructed and the link performance of OFDM-FSO communication system under K-PSK and M-QAM modulation was analyzed by using bit error rate as the evaluation index.The simulation results show that the bit error rate of the OFDM-FSO system under the exponentiated Weibull atmospheric turbulence model decreases with the increase of the carrier-to-noise ratio,and the bit error rate performance of the subcarrier using PSK modulation is generally better than that of the subcarrier using QAM modulation.The change trendency of bit error rate is slightly different under different turbulence conditions,especially,the change of BER are more obvious under the middle,strong turbulence conditions.Under the exponentiated Weibull model,the aperture averaging effect at the receive end can effectively improve the system’s BER.