Abstract：The types of shock impulse of ship shaft system are introduced. A shock dynamic model of ship shaft system is built up with the finite element method, and a software (SHAFTFE) for the ship shaft system dynamics and shock response simulation is developed on MATLAB. Dynamic characteristics of a ship power shaft system including propulsion shaft, propulsion electric motor and vibration isolator of electric motor, are analyzed by the SHAFTFE in the condition of different shock forces and parameters, and effects of the structure design parameters of the ship shaft system on the shock response are dealt with. It shows that the ship power shaft system will have a large motion on the action of base shock, so we must pay more attention on the shock character of the ship power shaft system during the design in order to increase the reliability and survival performance of whole ship.