光波经介质散射后的远场光学特性，包括光谱强度、光谱相干度以及光谱偏振度等，与散射介质的结构特征密切相关。近年来，光波弱散射现象的研究取得了较大进展，一方面，研究人员将散射体推广到各种介质，包括各向异性介质、半软边介质、椭球形介质等；另一方面，研究人员将入射光波推广到各种常见的光束，如随机电磁光波、平面波脉冲光束、非匀幅光束等。介绍了关于光波弱散射问题的主要研究成果，包括光波散射过程中的光谱变化现象、相干性变化现象、等价理论、互易关系以及光波散射逆问题等。

When light waves are scattered by a medium, the far-field optical properties including the spectral intensity, spectral coherence degree and spectral polarization degree, are closely related with the structure of the scattering medium. In recent years, much progress has been made in the research of weak scattering of light waves. On one hand, researchers have extended the scatterers to various scattering media, including the anisotropic medium, semisoft boundary medium, ellipsoidal medium, etc. On the other hand, the incident light waves are generalized to some commonly used light beams, such as the stochastic electromagnetic light wave, pulsed beam of the plane wave, non-uniform beam, etc. We introduce the main results of the research on weak scattering of light waves, including the spectral shift, spectral coherence, equivalence theory, reciprocity relation, inverse scattering, etc.