Abstract: For the purpose of investigating the effects on the arch-roof caused by thunderstorm downburst wind, the model fabrication of arch-roofs, and the physical simulation of wind field of thunderstorm downbursts are conducted based on the similarity criterion. And corresponding wind tunnel tests are completed. The parametric sensitive studies are conducted through varying the span, ration of rise to span and ration of height to span. The effects of the vertical wind field are also investigated by placing the building on different positions. It is found that the pressure distribution along the direction perpendicular to the ridge is closely linked with the ratio of rise to span, in case of that the center of an arch-roof is located at where the horizontal wind reaches its peak value. It is also revealed that the closer the roof is to the center of the downburst, and consequently the smaller the lift force is. Furthermore, the whole roof would be subjected to a rather heavy positive wind pressure in case of that the centers of the roof and downbursts coincide.