Abstract: In order to clarify the mechanism of attenuated blade tip effect on the aerodynamic performance of compressor rotor,the three-dimensional numerical simulation investigation is performed on the original model and six new models based on the experimental results of a subsonic compressor rotor.Following the analysis of total pressure ratio、efficiency and stall margin we draw the following conclusions: Attenuated blade tip improves the total pressure ratio and efficiency but at the same time decreases stall margin slightly;The improvement of suction surface curvature and the incidence of incoming flow is the main cause of pressure ratio enhancement;Attenuated blade tip weakened the adverse degree of leakage in the rear of blade tip and thus decresed the boundary layer separation loss、 mainstream / leakage mixing loss and wake loss and the pressure surface flow loss increases slightly,the total loss comes down.The increasing of the adverse degree of leakage in the front of tip,together with the improved incoming flow incidence of suction surface,makes the interface of mainstream / leakage move forward which cuts down stall margin of the rotor.