Abstract: The Dashankou Hydropower Station on Kaiduhe River, Xinjiang,is located in an area with highly active tectonic movement.The field evidance shows that the Hongshuigou fualt cutting through the station exhibited multi-phase activity by the end of late Pleistocene,while the last faulting on the small fault F9 occurred before late Pleistocene.We analysed the samples of fault materials collected along these two faults by means of analysis of microstructures,quartz surface structures and TL dating.The results reveal that the main period of activity is from the end of Pliocene to Early Pleistocene,and obvious activity had not occured since Middle Pleistocene along the segment of the Hongshuigou fault in engineering site;while the upper limit of time of last faulting is 90 ka along the F9. The dam area is a relatively stable area in modern tectonic activity and is a perfect engineering site.