The dynamic response of underground structure impacted by explosion is of great importance in the designing and evaluating of the protective engineering. The computational method for the dynamic response of straight-wall-round-arch structure to explosion seismic wave was investigated on the foundation of common deformation theory and matrix force method, and a rapid computation method is established. By the preseted method, the dynamic response of a typical straight-wall-round-arch structure was studied under different surrounding rock, subcrust and impact loading conditions. Results show that the rock grade, the thickness of subcrust and the loading mode all have notable influence on the structure’s dynamic response. The better the rock is, the lower the displacement and the internal force will be. And as the thickness of the subcrust increases, the peak value of the dynamic response decreases and delays.