The axial clearance leakage flow of liquid ring pump has important influence on its hydraulic performance. To suppress the axial tip clearance leakage flow of the blade and improve pump hydraulic performance, the 2BEA-203 liquid ring pump was selected as the research object, and the micro jet was designed in the axial tip of blade. The influence mechanism of micro jet on the leakage flow field and the performance of liquid ring pump was analyzed by numerical simulation. The analysis results indicated that the axial clearance jet can effectively restrain the leakage flow, and the efficiency and vacuum of liquid ring pump were improved in a certain range. A relatively high pressure region was formed at the outlet of the jet hole in the axial tip clearance, and the micro jet occupied the clearance passage. Part of the jet fluid interacted with the leakage flow, and the clearance vortex was formed. The leakage flow was blocked by the jet. As a result, the intensity of the leakage flow decreased, and the leakage vortex behind the suction surface moved forward. The leakage flow in the axial clearance had complexity temporal and spatial distribution characteristics. The distribution of turbulent kinetic energy increased gradually along the blade rotational direction from the suction area. Due to the inhibition of jet flow, the distribution of turbulent kinetic energy on the suction surface of jet impeller clearance was obviously weaker than that of the prototype impeller clearance. The intensity of leakage flow decreased along the chord direction. Part of the micro jet flowed into the blade axial clearance along the chord direction, and occupied the downstream clearance passage. The sealing performance of the blade tip clearance was improved.