Abstract: In order to save calcite crystal material and realize rectangular beam splitting of the polarized prism optical path, a calcite-BaF₂ ultraviolet rectangular beam splitting polarizing prism was designed by combining calcite and barium fluoride crystal. Ultraviolet light at the wavelength of 265.6nm was chosen as design example. The relationships of splitting angle of e Light and o light, splitting intensity ratio, incident angle and the wavelength of incident light, after incident light passing through the polarizing prism, were analyzed theoretically. And the relationship curve was drawn by the computing software. The results show that the splitting angle and right angle of the polarized prism is small. Light intensity splitting ratio of e light and o light is about 1:1. In the wavelength range of 240nm~400nm, the deviation of right angle beam splitting is less than 1.0° and the deviation of light intensity splitting ratio and 1 is less than 0.02. The prism has a wide light spectrum scope of application. The research provides an important and valuable reference to design, manufacture and application of rectangular beam splitting prisms.