Abstract: Research on the axial flow pump design optimization is beneficial for further improvement of its comprehensive performance.Taking an axial pump model as the research object, after experimentally verifying the accuracy of the numerical simulation, the inverse design method was used to design three typical loading distribution forms of axial pump impellers with front, middle, and back loading by modifying the loading distribution at the hub and shroud.The effects of different loading distribution forms on the performance of axial pumps were comparatively analyzed.The results demonstrate that controlling the loading distribution can effectively control locations of the maximum differential pressure on the blade surface.Back-loading at the hub and shroud improves the efficiency of the pump section under low flow and designed flow conditions, while front-loading effectively addresses the rapid decline in pump section performance (efficiency and head) under high flow conditions.Middle-loading provides a more balanced performance of the pump section.The efficiency of the front-loading, middle-loading, and back-loading axial pump models were 79.28%, 79.76%, and 82.92%, respectively, under designed conditions.Internal flow analysis reveals that suppressing the secondary flow in the middle and back of the blade working surface and the return flow at the impeller outlet contributes the most for improved performance of the back-loading model under small and designed flow conditions, while improving flow pattern in the guide vane under large flow conditions is the main reason for the enhanced performance of the front-loading model.This study can provide a reference for the optimized design of axial pump impellers.