Rochon prism is a familiar polarizer and beam splitter prism in laser technology. When using different refractive index of the glue, the light transmissivity is different. In addition, the two surface of the cementing layer is not always strictly parallel. And therefore its deflection angle and transmissivity is different from the value of the order. The influence of the refractive index and the non-parallel on the transmissivity and the deflection angle is researched using the knowledge of polarization optics and origin software. The result indicates that the refractive index is bigger, the transmissivity of light o, e is bigger, the splitting intensity ratio is bigger. The splitting intensity ratio of Rochon prism is strongly influenced by deflection angle θ. The different declining direction bring to the different transimissivity. The influence of θ on deflection angle is opposite to the influence on transimissivity.