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Pressure fluctuation measurement was conducted on the key points in an axial flow pump operating at 1450r/min，1200r/min,，1000r/min, respectively based on test. According to amplitude analysis, the results showed that the RMS tends to decrease firstly and then increase with the increase of flow rate at the impeller inlet, and decline in outlet of impeller and outlet of vane. The RMS varies more quickly with higher revolving speed. In terms of frequency domain, the base frequency at three revolving speeds is blade frequency at the impeller inlet, at the same time there also exists such frequency components: Fn, 2Fn, 3Fn at revolving speeds of 1450r/min and 1200r/min. And at the impeller outlet, frequency domain ranges from 0 to 8Fn; the base frequency appears in the range of 3Fn to 4Fn at revolving speeds 1450r/min and 1200r/min and shifts to higher frequency from 4Fn to 6Fn at revolving speed of 1000r/min. While at the outlet of guide-vanes, frequency domain of pressure fluctuation ranges from 0 to 12Fn; the base frequency appears in the range of 4Fn to 6Fn at revolving speed of 1450r/min and 1200r/min, and turns into another range from 6Fn to 8Fn at revolving speed of 1000r/min. The pressure fluctuation law was obtained with different revolving speeds and measuring points in the axial flow pump actual operation in the study, which provides reference for numerical simulation and lays a theoretical basis for weakening pressure fluctuation of the axial flow pump.