For a launch vehicle in erect status, an earthquake may bring severe consequence, such as the toppling failure of the launch vehicle. To ensure the safety of a launch vehicle during earthquake, analysis of earthquake time history response was executed. The distributions of peak moment and peak displacement in longitudinal direction of the launch vehicle were derived. Frequency-domain characteristic of moment response in key positions were researched. Seismic-relieving design was performed on the launch vehicle. Seismic response's influence disciplines of link stiffness between rocket and launcher, stiffness of isolation bearing were analyzed. The results show that: (1) the maximum of moment response occurs in tail of the launch vehicle, and the maximum of displacement response occurs in front of the launch vehicle; (2) the seismic response can be reduced significantly by changing link stiffness between rocket and launcher or equipping the launcher with isolation bearing.