Based on Navier-Stokes equations closed by SST k-ω turbulence model, the three-dimensional unsteady flow of a high speed centrifugal pump with inducer was numerically calculated. One-way fluid solid interaction method was utilized to process rotor system transient dynamic analysis by the help of ANSYS Workbench12.0, a computer aided engineering simulation platform. Flow induced vibration characteristic of this pump was analyzed subsequently. The result shows that initial stress from fluid has little influence on the intrinsic frequency of rotor system. Rotor stress increases with the pump flow, and the loads maximum position is located in the combination between pump shaft and the impeller. The displacement vibration at the top of the inducer changes periodic, and the fluctuation in the vertical direction is greater than the horizontal direction, whose frequency is the inducer blade passing frequency(267Hz). Bearing constraint surface vibration displays equilibrium, whose frequency is threefold of shaft frequency(379Hz).