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Improving the efficiency of pump is necessary for energy conservation, which also has very important significance on creating resource-saving society. When the working condition deviated from the designed condition, the flow direction at impeller outlet did not match well with the flow direction at guide inlet, which led to the efficiency drop of axial-flow pump. The inlet part of guide was changed with conventional guide, so as to improve the efficiency of axial-flow pump under off-design conditions and to broaden the high efficiency area. Firstly, the guide was divided into three parts: inlet, middle and outlet parts of guide. Based on numerical simulation and model experiment, the influence of different inlet parts of guide on the hydraulic performance of axial-flow pump was studied. The results showed that the inlet angle of guide affected the flow regime and hydraulic loss in the guide vane, which further affected the hydraulic performance of axial-flow pump. By rotating clockwise with appropriate angle under the original inlet angle of guide, the high efficiency area can be significantly broadened and the efficiency under low head and large flow-rate condition can be increased.