Abstract: In order to study the crack failure characteristics of the auxiliary feed pump impeller, the pressure pulsation response law of the auxiliary feed pump casing measuring point under different impeller crack lengths is explored based on CFD, and the CFD results are verified by the vibration monitoring data of the auxiliary pump feed pump in the presence or absence of impeller cracks. The research shows that the pressure pulsation response of the pump casing can better reflect the crack failure characteristics of the auxiliary feed pump impeller; when there is a crack in the auxiliary feed pump impeller, there will be a clear sideband with a width of rotating frequency of the blade passing frequency in the vibration spectrum of the pump casing measuring point.