Abstract: To study the effects of the interaction between the wind and wave on the buffeting response of coastal bridges in extreme wind and wave environments, the CDRFG method was used to generate the inlet turbulence of the LES. A thin plate was taken as the research object, and a moving solitary wave was used to simulate the extreme wave. Then, the effects of presence or absence of the solitary wave on the flow field, on aerodynamic forces, and on buffeting response of the thin plate were analyzed at different clearance heights. Also, the impact mechanisms were explored through theoretical methods and other means. The results indicate that the solitary wave has significant shielding effects on wind speeds and turbulence intensities in the range of 2.5 times and 4.5 times the wave height, respectively, resulting in a decrease in wind speeds and an increase in turbulence intensities. When the solitary wave propagates upstream along the thin flat plate, the vortex shedding generated at the peak position of the solitary wave will change the flow field and fluctuating energy distribution around the thin plate, and the dominant frequencies of the aerodynamic forces of the thin plate are significantly changed, compared with those with the absence of the solitary wave. At the same time, vibration amplitudes of the thin plate increase significantly, and the vibration energy is mainly concentrated near the natural frequencies of the thin plate. The lower the clearance height, the more obvious the above phenomena. When the solitary wave propagates downstream along the thin plate, the vortex scales around the thin plate at different clearance heights are smaller and the energy is lower, and the dominant frequencies of the aerodynamic forces of the thin plate are consistent with those without the solitary wave. At this point, the lateral displacement of the thin plate continues to increase due to the peak torsional angle of the thin plate reaching the peak value, but as the solitary wave moves far from the thin plate, the vibration amplitudes in all directions gradually decrease.