为了用散射法研究单层薄膜表面粗糙度的变化规律，以光学薄膜矢量光散射理论为基础，分析了单层二氧化钛薄膜分别在完全相关和完全非相关模型下的偏振双向反射分布函数，以及P偏振入射光引起的P偏振的BRDFpp随散射方位角的变化关系。理论研究结果表明：随着散射方位角的变化，P偏振入射光引起的P偏振的BRDFpp强烈依赖于膜层界面粗糙度的相关特性。在完全相关模型下，随着入射角的增加，BRDFpp随着散射方位角变化时所出现的谷值会随着入射角的增加而减小。

In order to study the changing rule of single layer thin film surface roughness using light scattering, the polarized bidirectional reflectance distribution function(P-BRDF) of the single titanium dioxide thin film at fully correlated and uncorrelated model were researched respectively based on the vector scattering theory of optical thin film. The relationship of scattering azimuth angle and BRDFpp, P-polarized scattered light caused by P-polarized incident light, was researched. The theoretical results show that BRDFpp strongly depends on the correlation between interfaces roughness of thin film and substrate with azimuth angle changing. The scattering azimuth angle of BRDFpp valley value can decrease with the increase of incident angle at fully correlated model. The result is reverse to uncorrelated model. BRDFpp does not appear valley value as the change of scattering azimuth angle.