Owing to the fact that several county towns in Sichuan were badly damaged, especially Beichuan County was in ruin by the Wenchuan earthquake on May 12,2008, selection for town sites has become the important task for reconstruction of earthquakestriking areas. Field investigation and comprehensive analysis show that the basin is of good basement and has no fractures developed inside the basement, although it is located in an intensive active tectonic zone. The basin is in a relatively state blockso called safety island. Thus the Leigu basin is of practical value for reconstruction of Beichuan County. Based on field investigation of active faults and seismic hazards, applying the theory of Safety Island originated by Prof. Li Siguang, this paper discusses the crustal stability of Leigu basin, and analyzes the characteristic of the engineering geological and hydrological conditions, which can provide geological evidences for reconstruction and relocation of Beichuan earthquakehit area.