Abstract: Based on the terrain of the bridge site in coastal areas, using the downburst experimental device of the impacting jet model and refining 3D terrain conditions simulation, wind tunnel test and Computational Fluid Dynamics (CFD) method were used to investigate the wind characteristics of the topographic under the effects of steady and moving downburst. The results show that compared with the flat terrain under the jet, the slope will have an accelerating effect on the wind field of the downburst flow, with largest wind velocity difference as 3.1%. The experimental results of steady-state downburst are in a good agreement with the numerical simulation results, basically reproducing the wind field characteristics under the action of downburst. Specifically, near-ground wind speeds exhibited a rapid increase followed by gradual attenuation. Furthermore, the peak and valley wind speeds recorded during moving downburst tests aligned consistently with simulation predictions. The result is of a practical significance for further research on the response mechanism of bridges located in coastal areas under the downbursts and for improving bridge performances.