In a typical polarimetric dehazing method, the estimation of the degree of polarization (DoP) of the backward scattered light is a key factor to affect the dehazing effect. In the present paper, based on the polarization maintaining characteristic of the circularly polarized light in the Mie scatting media, the traditional polarimetric dehazing method was optimized which was suitable for use in the strong scattering environment. The variation patterns of the DoP of the light field received by the CCD, in the light source illuminations with different polarization states and in different densities of the scattering particles, were discussed, based on which a simple and easy method for estimating the DoP of the scattered light was proposed. This method can improve the effect of polarimetric dehazing method, without increasing the complexity of the system. It can be seen from the experiment results that under a condition of strong scattering, the present method can provide the dehazed images with an EME value being 20.4% higher than that by the traditional method. In addition, in this method, it is not necessary to determine the background region(s) as in the traditional method for polarimetric dehazing, thus lowering the calculation complexity.