Abstract: In order to study the influence of wave on water entry of cylinder, a CFD method was presented to numerically simulate the physical process of cylinder vertically entering water in regular wave. In this method, free surface capturing method and Cartesian cut cell mesh system were adopted to treat moving free surface and solid boundary. In combination with the theories of a pistontype wavemaking and sponge damping waveabsorbing, the CFD method was applied in the implementation of numerical wave making and absorbing. Furthermore, the effect of wave parameters (wave height, wave period, wave phase versus cylinder touching free surface, and so on) on the hydrodynamic was analyzed. Finally, the application case of lifting operation from a crane ship in wave was numerically simulated, and the tension variation of wire and motion characteristic of cylinder under different working conditions were mainly studied.