为解决偏振子午面蒙特卡洛法的计算结果与测试结果存在出入的问题，文中提出了一种限定接收范围的改进算法。偏振子午面蒙特卡洛法计算过程中采集整个截面的前向散射光，但实际接收装置通常接收部分前向散射光，这是引起偏振子午面蒙特卡罗法的计算结果与实验结果存在出入乃至失配的重要因素之一。为此，改进算法限定了前向散射光的接收范围，限定的接收范围与实际接收范围一致。采用原算法和改进算法分别模拟 45°线偏振光和水平线偏振光在聚苯乙烯悬浊液中传输。选用粒径 1 μm 的聚苯乙烯悬浊液开展验证实验，通过对照测试结果，改进算法相比原算法能够更好地匹配实测结果。通过计算单个微粒的偏振状态保持情况，阐明改进算法提高计算精度的作用机理，即前向散射角愈外延，散射光的偏振态变化愈剧烈，而改进算法规避掉了绝大部分前向散射角外延程度较大的散射光。

To solve the problem of discrepancies between calculation results and test results of the polarization meridian Monte Carlo method, an improved algorithm which can limit receiving range was proposed. All forward scattered light was received generally in real receiving devices in the process of calculation, but part of forward scattered light was collected. This is one of the important factors causing discrepancies and mismatch between calculation results and test results of the polarization meridian Monte Carlo method. For this reason, an improved algorithm was proposed to limit receiving range of forward scattered light. Receiving range of the improved algorithm was consistent with real receiving range. Original algorithm and improved algorithm were used to simulate the propagation of 45°- and horizontally- linearly polarized light in polystyrene suspension, respectively. Then, the polystyrene suspension with particle size of 1 μm were selected to carry out verification experiments. Compared with the original algorithm, simulation results of the improved algorithm were closer to measured values. Finally, the polarization state distribution of a single particle was calculated to clarify mechanism of improved accuracy. Retention of polarization state(RoPS) changes drastically as forward scattered angle extends. Improved algorithm avoids most of forward scattered light with larger forward scattered angles.