The present invention is a sealed end face self-compensating radar water slide ring which is mainly formed by a static shaft, a rotation shaft, a shell and a mechanical seal. The sealed end face self-compensating radar water slide ring is used for supplying cooling water to a cooling system in a rotation antenna cabin, ensuring the circulation of the cooling water in a cooling water source and the cooling system in the antenna cabin and solving a water slide ring key leakage problem. According to the sealed end face self-compensating radar water slide ring, water inlet and outlet are at the lower end of the static shaft, return water inlet and outlet are at the upper end of the rotation shaft, water inlet and outlet channels are at two sides of the static shaft and the rotation shaft, the space between the water inlet and outlet channels is sealed by a maze, the structural complexity of the water slide ring can be effectively reduced, an self-designed mechanical seal with compact structure is used by the seal among a water inlet channel, a water return channel and the outside, the mechanical seal has an automatic compensation function, and the reliability and life problems of mechanical dynamic seal are solved. The sealed end face self-compensating radar water slide ring can be directly used in a large modern power radar with the need of liquid cooling and has the advantages of compact structure, low cost, large diameter, high reliability, long life and good maintenance.