Abstract In this study, the internal fluid noise and external noise of the pump are studied, and the experimental and simulation methods are put forward respectively. Based on the CFD/CA tool, the coupling between the flow field and the sound field is calculated. The propagation law of the sound field induced by the flow induced noise is solved. The changes of the sound pressure level and the frequency domain of the flow noise at the time of reflow or cavitation are analyzed. Before the cavitation, the flow-induced noise spectrum is discrete. Concentrated in the low frequency region, and at high frequency fast decay, with the cavitation coefficient gradually decreases, the interaction between impeller and guide vanes become the main cause of noise induced by pump. The noise experimental test is based on the four-terminal network method, and found that the pump noise is mainly related to the pump flow, and the noise of the pump unit is mainly related to the pump running condition.