Abstract: In the pre-feasibility study for the Wudongde Hydropower station,six alternative dam sites,i.e.,Luchelin,Jinshangbao,Hemengkou,Baitan,Santaizi and Wudongde were evaluated.The Reshuitang Fault traverses both the Hemengkou and Baitan dam sites,therefore,it is very important to understand activities of the fault.In order to identify the scale,property and activities of the fault,the authors made a detail analysis of the geomorphologic,lithologic and karstic features along the fault based on interpretation of the aerial photos and field investigation.With geodating and microscopic structural analysis,the authors concluded that the fault was active before middle Pleistocene Epoch,but became less active afterwards and completely ceased after late Pleistocene Epoch.Additional seismic analysis confirmed that Reshsuitang Fault is no longer active.