无线光通信(FSO)系统的性能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模型为基础，使用拟合概率分布替换常用的对数正态分布，建立了FSO系统差错性能的数学仿真模型，改进了湍流条件下系统误码率计算公式，并且进行全天的验证实验。实验结果显示，光强概率分布对系统性能有显著的影响，原有公式在某些情况下的计算结果有较大偏差，而改进公式的计算结果具有更好的适应性和准确性。该改进公式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, which is influenced by atmospheric turbulence. Research about evaluating system error performance according to parameters of system and atmosphere is a subject with certain practical significance. Based on both optical turbulence channel and photoelectric detection model, a mathematic simulation model of error performance for FSO system is established. A modified expression of bit error rate for FSO system through turbulent atmosphere is proposed, and an experiment of 24 hours′ duration is carried out to test the expression. It shows that intensity probability distribution has a significant influence on system error performance. The results of original expression are inconsistent with experimental data on certain conditions, and the modified expression has better applicability and accuracy. The modified expression can lead to an efficient performance evaluation and provide reference to correlative researches.