In the present study, numerical algorithms for a high-speed planing ship were taken into account. The Rankine source panel method was applied to predict a flow phenomena around a ship. The Kelvin type free surface boundary condition and the exact nonlinear free surface boundary condition were compared to predict the wave system generated by the ship and the trim and sinkage state of the ship also were introduced. In order to deal with complex geometries of the planing ship the panel cutting method was adopted. The developed numerical analysis algorithm were applied to the R/V Athena ship and the numerical results were compared with the experimental results.