The invention discloses an underwater polarization image fusion system based on a bionic vision mechanism. The system comprises a cluster light underwater polarization imaging module based on a non-uniform light field, a polarization parameter image calculation module, an image storage module, an image grading fusion module and an output display module. First of all, the non-uniform light field can be established by taking a cluster light source as underground illumination, underwater polarization images are extracted by use of a bionic mantis and shrimp vision polarization perceiving mechanism, and thus backward scattering caused by particles suspended in water is inhibited; and then, by use of information correlation and complementarity between polarization parameter images, based on a human eye vision feature, a grading fusion model of the images is constructed, and thus feature and multi-scale fusion of the polarization images is realized. According to the invention, the sharpness and the contrast of the underwater polarization images can be effectively improved, detection and analysis of underwater targets are facilitated, and the detection precision of the underwater targets is further improved.