Based on the spectrum detection technology of dispersion polarization, the optical polarization characteristics of emulsified oil particles and the Mie scattering physical model have been emphatically studied, and the spectrum detection system of dispersion polarization degree has been constructed. In the wavelength range of 400-700nm, the spectral reflectance of 301 bands was collected for four samples. Combining the Bessel function and Hankel function, the relationship between the wavelength of incident light and the polarization amplitude vector of the scattered light has been derived, and a new characteristic parameter has been extracted: the degree of dispersion polarization (DODP). Under darkroom conditions, the emulsified oil samples ND18 and ND75 were measured, and the polarization value of the sample at each measurement wavelength was calculated using the dispersion polarization formula, verifying the feasibility of detecting emulsified oil based on DODP value. This study found that although the solution of Mie scattering is derived from the diffraction of a single sphere. As long as their diameter and composition are the same, and the distance between each other is greater than the wavelength, They can also be used to diffract any number of balls. There is no coherent phase relationship between lightly scattered by different spheres, and the total scattered energy is equal to the energy scattered by a sphere multiplied by their integers. When the angle between the observation plane and the vibration direction of the incident wave electric vector is ϕ=0 or ϕ=π/2, the scattered light component Eθ(s) and Eϕ(s) disappears. Since the particle size of ND18 is smaller than that of ND75, the forward scattering lobe of ND18 is larger, and the ratio of forwarding scattering to backward scattering is small. Under the same lighting conditions, the multiple scattering of ND75 is more serious than that of ND18. According to the theory of path correlation matrix, multiple scattering is likely to cause depolarization, and secondary radiation waves will spread and distribute in the angular domain. Therefore, the number of scatterings generated on the surface of the emulsified oil measured is proportional to the damping capacity of the incident light energy. Due to the difference in energy dissipation of incident light on the surface of emulsified oil, the energy dissipation rate is proportional to the component of the forward scattering amplitude in the direction of the incident wave vector, and the degree of polarized scattering of emulsified oil is different from the degree of polarized scattering of incident light. Experimental results show that DODP can reflect emulsified oil’s depolarization ability caused by multiple dispersions. Since the simulated light source was natural light, it was very convenient to calculate the polarization parameters of scattered light, which could greatly shorten the data processing time and reduce the experimental error. DODP can identify emulsified oil in seawater and distinguish the concentration of pollutants and accurately identify the edge diffusion of emulsified oil.