When a large ship is advancing in waves, ship undergoes the hydroelastic response, and this have influence on structural stability and the fatigue destruction etc. of ship. The main objective of this research is to develop an accurate and convenient method on the hydroelastic response analysis of ships on the real sea states. We analyzed hydroelastic responses, which is formulated by finite element method. The numerical approach for the hydroelastic responses is based on the combination of the three dimensional source distribution method, the dynamic response analysis and the spectral analysis method. The calculated results show good agreement with the experimental and calculated ones by Watanabe.