Abstract: Abstract：[Objective] To investigate the coupling effect of ship nonlinear wave load and transient high-amplitude slamming load in view of the whipping response of ships under severe sea conditions. [Methods] Two-way CFD-FEM fluid-structure interaction method was used to carry out numerical simulation for S175 ship, and the results were compared with the test results and the 2D linear strip theory. The segmented ship model with variable cross-section elastic backbone test of ship was carried out, and the analysis of bow’s slamming load and high-frequency nonlinear whipping characteristics is carried out based on the two-way fluid-structure interaction method of CFD-FEM. The results were compared and verified with the model test. [Results] The influences of wave slamming load on whipping response of bow cannot be ignored. The second order high-frequency component induced by whipping accounts for 59.86% of the low-frequency wave bending moment under the sixth order sea state.[Conclusion] The two-way CFD-FEM fluid-structure interaction method can calculate the whipping response accurately. The nonlinear wave induced load and dynamical structure response of the ship under high sea conditions are affected by the transient slamming load of the bow. The high-frequency whipping response should be taken into consideration in the design stage and assessment of the ship structure’s safety.