The earthquake coefficient method is used for aseismatic calculation of tunnel in traffic tunnel specification in our country, but the method is not in accordance with the practical engineering and seismic damage when tunnel is buried very deep, because the inertia force of overlaying soil is overestimated. In order to improve the adaptability of earthquake coefficient method, it is necessary to modify it. In this paper, the aseismatic calculation based on earthquake coefficient method is carried out，and the limitation of the method is analyzed. Then earthquake coefficient method, response displacement method, and dynamic analysis method are applied to tunnels’ aseismatic calculation in V class surrounding rock at different widths of the cavity. Finally, the advisable calculation heights of tunnel overlaying soil with earthquake coefficient method in V class surrounding rock is presented, which can be referenced in aseismatic calculation of tunnel engineering.