根据算法的准确性、稳定性和快速性原则，讨论了Mie散射和Rayleigh散射的数值算法。将Mie散射理论及Rayleigh散射理论的Matlab数值结果与Wiscombe结果对比分析，证明了此Matlab程序的正确性。在此基础上，确定了当颗粒粒径参量x＜0.3时采用Rayleigh散射理论来确定前向某一角度范围内散射光能分布，从中求得颗粒的粒径大小和分布，具有比Mie散射理论算法快速性的特点。该方法为某些测试对象(颗粒与分散介质相对折射率、颗粒种类等)确定、微小颗粒的在线测量提供了理论支持。

According to the accuracy, stability and fast property of algorithms, the numerical algorithms of the classical Mie scattering and Rayleigh scattering were presented in this paper. Compared the numerical results acquired from the Mie scattering theory and Rayleigh scattering theory by using Matlab with Wiscombe′s numerical results, the results acquired from Matlab programs were also accurate. According to Matlab numerical results, the forward light scattering distribution in a certain angle can be determined by Rayleigh scattering theory when the size parameter x is less than 0.3. The size distribution can also be determined. The algorithm of Rayleigh scattering theory is more efficient than the corresponding algorithm acquired from Mie scattering theory. This simplified method can provide theoretical support for online measuring micro particles when some test objects(the relative refractive index, particle type) are determined.