Optical thin film polarization splitting prism is one of the important parts for modern photoelectric display, test and information transmission systems. However, conventional optical thin film polarization splitting prism has some technical difficulties, such as poor chemical stability of substrate, narrow polarization splitting bandwidth and small application angle. By studying the principle of Brewster angular polarization splitting and the polarization separation effect of interference cut-off filter, the polarization splitting bandwidth of polarization splitting prism is extended by combining two design methods. The polarizing beam splitters of p-polarized light 0.44～0.64 μm, Tave≥95%, Rave≤5%, and s-polarized light 0.44～0.64 μm, Tave≤5%, Rave≥95% on the BK7 substrate of Schott optical glass with good chemical stability are prepared. This kind of optical thin film can be used to design and optimize wide-band, wide-angle and high polarization extinction ratio polarization splitting prisms on different glass substrates. It provides a new theoretical basis and preparation scheme for the design and preparation of polarization splitting prisms.