Abstract: In order to design a modular structural reflected polarizing prism which has an equal splitting angle,the construction of the prism was analyzed in theory by combining the reflecting principle in anisotropic crystal and practical application,and a structure angle was found which can make the splitting angle equal.Based on the angle,two aspects of the prism were calculated,i.e.the relationship between the degree of asymmetry and the incidence angle of light wave,and the relationship between the degree of asymmetry and incident wavelength.The results show although the degree of asymmetry has a small fluctuation,the design proposal is still successful.