Abstract: This paper presents the geological investigation on the characteristics of the faults observed in the engineering tunnels around Daliushu hydropower dam site.The faulting materials were used to test the latest activity age of the fault.The samples are dated younger than 120Ka by ESR dating method in laboratory.The dating results illustrate that the faults observed in the engineering tunnels around Daliushu hydropower site have not been active faults since late Pleistocene.