Water Resources Agency planed to build Gaotai Dam in the upstream of shihmen Dam for storaging more water resources. A previous study confirmed that Gaotai dam was the possible dam site in Da-Han River and carried out relevant investigation in 2004. Based on previous investigation results of topographic surveying (1:1000), geological mapping, drilling, in situ and laboratory rock mechanics tests, the proposed dam site of Gaotai reservoir is suitable for building a new gravity dam. Hence, for feasibility study further site investigation is needed. This project is based on geological target for the palning of Gaotai Dam.