The analysis of the polarization characteristics of reflected light and backscattered light can provide theoretical support for the research on key technologies of underwater active light source polarization imaging. The influence of the parameters of different light sources, environments, and reflective targets on the characteristics of the reflected light was analyzed. The difference in the degree of polarization between the reflected light and the backscattered light was also determined. A Monte Carlo numerical simulation method based on a combination of Mie scattering theory and polarimetric bidirectional reflectance distribution function was used to establish underwater photon scattering and reflection-tracking models. Through simulation and analysis of the influence of the underwater environment system on the polarization characteristics of the backscattered photons and the reflected photons of different polarization types of the incident light, the following conclusions are drawn. First, in the same condition, the difference in polarization characteristics of backscattered and reflected light of circularly polarized light was larger than linearly polarized light. This is due to the better polarization-maintaining ability of circularly polarized light than linearly polarized light. Second, when various types of materials were used as reflective targets, the difference in their complex refractive indices changed the polarization of the reflected photons. And the complex refractive index had varying effects on the two types of polarized light.