Seismic risk analysis is the key to seismic protection of engineering constructions. Based on the site of Aerjin mountain tunnel project, this paper used probabilistic seismic risk analysis method to divided the hierarchical space of potential source area model in this area, and determined the seismicity parameters and corresponding attenuation relationship of source model by referred to other seismic activities, The 50 years exceeding probability of seismic risk is calculated based on the level of 63%, 10% and 5% in this area. The research results can be used as a reference material for the Aerjin tunnel project site with respect to the seismic risk and risk assessment , and can be provided reference value for the seismic risk analysis of similar projects, too.