With the aim to explore the influence of inlet guide vane on the cavitation performance of centrifugal pump, the cavitation experiment on IS 150-125-250 centrifugal pumps with original design inlet guide vane has been conducted. Using the Zwart-Gerber-Belamri cavitation model, the 3D unsteady cavitation flow in centrifugal pump flow channels has been simulated. The result shows that the negative pre-whirl by guide vane regulation could improve the cavitation performance of centrifugal pump in a certain angle range, and the cavitation performance was deteriorated when the angle exceeds the certain value. The positive pre-whirl regulation deteriorated the cavitation performance of centrifugal pump, and it become even more serious with the increasing positive pre-whirl angle. The analysis of the vapor volume fraction distribution in impeller channels indicates that the negative pre-whirl angle reduced the cavitation zones in impeller, and the positive pre-whirl angle expanded the cavitation zones in impeller channels.