On the basis of previous work that oil spill polarized light detection methods, the polarization station of reflected light in in the Poincare Sphere is analyzed, and physical analysis of the detection methods is given. Using linearly polarized light as incident light, with the incidence angle near the Brewster angle, the trajectory of reflected light polarization state in the poincare sphere is used to identify different types of oil、 water、 oil film thickness. In further, experiments are condusted with 650, 850, 1064, 1310 and 1550 nm wavelengths linearly polarized light and different oil, and experimental results and physical analysis are well confirmed.