Ground fissures are defects on earth’s surface caused by endogenetic agents, external agents and human activities. Under these adverse geological conditions, ground fissures must have some effects on site earthquake response. This paper aims at providing research and engineering assessment on site seismic effects of ground fissures. A finite element numerical analysis is made to study the ground motion effects of ground fissures in Xi’an City. The influence characteristics and influence scope to peak ground acceleration and response spectrum are obtained. The results of the analysis provide a reference to engineering structures’ seismic resistance and hazards avoidance.