The tip leakage flow of axial-flow pump has an important influence on the internal and external characteristics of the pump. The relationship between the blade loading distribution patterns and tip leakage flow was established from the perspective of controlling the blade load. Based on the three-dimensional inverse problem design method, the impeller models of axial-flow pump with three typical blade loading distribution patterns of front load, middle load and after load at the blade tip were obtained. The influence of the blade loading distribution on tip leakage flow and induced leakage vortex flow of the axial-flow pump was studied based on three-dimensional turbulence simulation technique. It was found that compared with the front-loading type impeller and the middle-loading type impeller, the after-loading type impeller can effectively eliminate the low-pressure area near the blade inlet, which was beneficial to the cavitation performance of the impeller. The external performance simulation results showed that the pump performance was improved at the small flow rate and the hump phenomenon of the discharge-head characteristic curve was effectively suppressed, which was consistent with the experiment results. At the same time, the impeller with after load had better pressure pulsation performance under the condition of small flow rate.