自由空间光通信(FSO)系统的性能由于受大气湍流影响会产生剧烈波动。根据系统和大气参数评估系统差错性能的研究具有现实意义。以大气湍流信道和光电探测两个模型为基础，建立了FSO系统差错性能的数学仿真模型，提出了湍流条件下系统误码率计算公式。对仿真结果与弱湍流条件下获得的实验数据进行了比较，并依据此模型对光强起伏和背景噪声等因素的影响进行仿真。仿真结果表明，基于该模型的仿真结果与实验数据一致，光强起伏是引起系统性能波动的主要因素，最优判决阈值需根据实际大气条件进行调整。该模型可有效评估湍流条件下FSO系统性能，并为相关理论研究提供参考。

Performance of free-space optical communication (FSO) system fluctuates greatly due to influence by atmospheric turbulence. Research about evaluating system error performance according to parameters of system and atmosphere is a subject of current interest. Based on both optical turbulence channel and photoelectric detection model, a mathematic simulation model of error performance for FSO system is established, and an expression of bit error rate for FSO system through turbulent atmosphere is proposed. Results of simulation are compared with experimental data obtained under weak turbulence condition and the model is used to characterize factors in turbulence, such as intensity fluctuation and background noise, etc. Simulation results are shown to be consistent with experimental data, intensity fluctuation is a chief factor of system performance fluctuation, and optimized threshold should be adjusted according to pratical atmosphere. The presented model can lead to an efficient performance evaluation and provide reference to correlative theoretical researches.