In order to evaluate the characteristics of in - situ stress distribution in Ahai Hydro - power Stations dam site, Jinshajiang River , the hydro - fracturing measurement and analysis are conducted. Results reveal t hat the stress magnitude is relatively low and the maximum horizontal principal stress' direction is NW. The later character should be attributed to the combine d action of dam sites geomorphology and horizontal tectonic stress conditions, and is also influenced by the regional geostructural fractures.