To solve the problem of low resolution of underwater polarization imaging images, a method to improve the resolution of active underwater polarization imaging images is proposed, which includes an optimal orthogonal polarization image group acquisition method, and an accurate estimation and optimization method of the polarization degree of backscattered light and target reflected light. An experiment is carried out to improve the resolution of underwater image restoration based on linear polarized light active illumination. The experimental results show that the image group with the lowest correlation degree is used as the orthogonal polarization image group among multiple groups of orthogonal polarization images, and the scattering depolarization coefficient is used to accurately estimate and optimize the polarization degree of backscattered light and target reflected light, and the final restored target image has higher resolution. Compared with the existing image restoration algorithms, it has obvious advantages and is suitable for water media with different material objects and different turbidity.