The performance of centrifugal pump with whole flow field was analyzed by using CFD technique. The blocking strategies and mesh generation on domains of the pump were presented. Numerical simulation of whole flow field model and simple model in CFX for the pump was then carried out and the reason of the difference between two models was compared. It was verified that the cavity indeed had effects on simulation results. The whole flow field model showed a higher accuracy than the simple model, and the flow pattern of two models were also different. The relationship between the sub-flowrates through front cavity and the overall performance of the pump was evaluated. The simulation results of whole flow field model and the measured results were compared. The relative errors of the head and efficiency were 0.79% and 0.9% at the normal flow rate Qd, while they were 6.24% and 9.61% at 0.2Qd. The accuracy of numerical simulation should be improved at minimal flow point.