在闪烁指数定义的基础上，综合考虑背景光噪声、探测器固有噪声和散粒噪声等影响闪烁指数测量精确度的因素，修改了测量系统的数学模型，并对现有数据处理方法做出改进。在1 km距离上进行了激光水平传输实验，分别采用了现有方法和改进方法处理实验数据，并对获取的3种闪烁指数进行了比较。实验结果显示：修改后数学模型相比现有模型更符合实测值；相比系统本底噪声，探测器散粒噪声要高出一个数量级，将会严重影响测量准确度；在信噪比有较大波动的条件下，改进方法受到的影响小于现有方法；在信噪比较低时，改进方法的准确度优于现有方法。

Considering system background noise, detector inherent noise and shot noise, the mathematical model of scintillation index measurement system was amended and the current method for data processing was modified. An experiment of laser propagation was carried out at the range of 1 km, and the experimental data were processed with the original and the modified methods. The results show that the amended model is more consistent with experimental data than the original one; shot noise is one order of magnitude larger than system background noise and it influences the accuracy of measurement seriously; the fluctuation of signal-to-noise ratio(SNR) has less influence on the modified method than on the original method; and the accuracy of the modified method is higher than the original one in low-SNR condition.