In order to predict the stress and deformation during the transient  state of the centrifugal pump startup period,a coupled solution of flow field in the pump and structural response of the blades was established by using Fluid-Structure Interaction method.The flow field prediction was based on the Reynolds-averaged N-S equations and the SST turbulence model;and the structure prediction is based on elastic structural dynamic equation. Based on the transient numerical simulation results, the Fluid-Structure Interaction method was used to solve the internal flow field and the structure field during the centrifugal pump startup period.The results showed that: the maximum equivalent stress and strain of the blade show a vibration on the rise, the vibration intensity decreases first and then increases;A intense ocurrs in the impeller inlet near the hub,and the blade deformation shows a trend increasing from hub to shroud;The maximum equivalent stress and strain of the blades are greater than that in the steady-state conditions.