自然环境中存在大量各种各样的悬浮颗粒，有关粒子散射特性的研究具有广泛的应用价值。现有的理论计算较为复杂，且研究对象多为均匀球体模型，忽略了粒子内部组成结构的差异。通过分析双层均匀球体模型消光效率和吸收效率的计算过程，将异常衍射近似方法扩展到多层均匀粒子，并给出相应的误差比较，说明该方法的实用性。以海洋浮游微生物为例，着重讨论了双层均匀粒子具有不同内外球体参数以及内球和外球中心偏离情况的散射特性。仿真结果表明除了尺寸、折射率等参数，粒子的不均匀结构对前向散射也有作用，当内外球体参数相差较大时，有必要考虑结构因素对散射特性的影响。

There are many kinds of suspended particles in natural environment, and research on scattering characteristics of particles has extensive application value. The existing theoretical calculation is complex, and it is often based on assuming a homogeneous composition sphere model without the difference of particle’s internal composition structure. Through the analysis of calculation for extinction and absorption efficiency of two- layered homogeneous sphere model, the anomalous diffraction approximation method is extended to multilayered homogeneous particle model. The corresponding error comparison illustrates the usefulness of the method. The scattering properties of two- layered homogeneous particles with different internal and external sphere parameters and offcenter deviations are discussed by taking marine plankton as an example.The simulation results show that except for size and refractive index, particle heterogeneous structure also plays a role on the forward scattering. When the difference between inner and outer sphere parameters is large, it is necessary to consider the influence of structural factors on the scattering properties.