Abstract: In order to suppress the cavitation instability caused by tip clearance leakage vortex of the high-speed inducer,a structure（ an annular groove） that can absorb the leakage vortex on the upstream and downstream of the high-speed inducer was set up,and 5 kinds of annular groove schemes were designed. The inhibition mechanism of cavitation by different annular groove schemes was studied by means of experiment and numerical calculation. The results show that the cavitation first appears at the position where the leading edge of the suction surface of the inducer intersects the shroud,as the pressure at the inlet of the pipeline continues to decrease,the cavitation continues to develop into the inducer passage and then spreads to the back of the centrifugal impeller blade. The annular groove can effectively inhibit the occurrence of clearance leakage vortex cavitation,asymmetric vortex cavitation and rotating vortex cavitation. The inlet pressure and the head of the centrifugal impeller are improved almost without affecting the efficiency and the head,the cavitation performance of the centrifugal pump is improved effectively. But at the same time,it is found that when the axial distance between the annular groove and the inducer is L₃=-10.0 mm and L₄=-12.5 mm,the annular groove can interfere with the flow state of the fluid in the inducer,affecting the work and energy exchange of the inducer,that is,when the annular groove is matched with the inducer,there is the best axial position between them. At this time,the axial distance between the annular groove and the inducer is L₁= 2.5 mm.