In order to solve the problems of blurred image and low contrast caused by the absorption and scattering of underwater light by turbid water, an algorithm of underwater image optimal restoration based on global polarization parameter estimation was proposed. Firstly, the local minimum filter was used to estimate the underwater background light image, Stokes vector principle was introduced to calculate the degree of polarization image, and normalized mutual information was used to further optimize the degree of polarization information, to obtain the best reconstructed polarization parameters in the imaging region. Secondly, a method of image reconstruction based on morphology was used to estimate the infinite underwater background light intensity values automatically. Finally, the underwater simulated environment platform was built, and the underwater polarization image was acquired in real time through a single channel fast rotating polarization detector. In order to verify the effectiveness of the algorithm, the three objective evaluation indexes were adopted as quantification to evaluate indexes factors. The results show that the algorithm is better than the other underwater image restoration methods.