利用折射定律，介质膜两侧折射率不同时多光束干涉理论和菲涅耳公式，精确推导了双沃拉斯顿棱镜的光强分束比的具体表达式。以公式为基础，通过Matlab软件数值模拟作图分析光强分束比随入射角、入射波长和结构角的变化关系曲线。结果表明：在棱镜为介质胶合型时，光强分束比随入射角和入射波长的变化很小，光强分束比基本为1；棱镜为空气胶合型时，光强分束比随入射角，结构角和波长的变化很大。两种情况下，光强分束比随各参量的变化基本呈周期性变化。

The exact expression about the intensity splitting ratio of double Wollaston prism is given based on reflection law, multiple-beam interference and Fresnel formula. The effect of the incident angle, the wavelength of incidence and the cut angle on the splitting ratio is given by Matlab software simulation, which results in the fact that the influence of incident angle, wavelength and cut angle on the intensity splitting ratio is negligible for glue spaced prism, and tremendous for air spaced types. The intensity splitting ratio varies periodically with these parameters for both types prism.