Abstract:Rizhao reservoir is a large (second grade) reservoir built in 1959. It locates in middle reach of Futuan River which is 16km far from the west of Donggang district in Rizhao city. Its control basin area is 548km2. It is one of the most important water source for ensuring national economic development in Rizhao city. In recent years, accompanying with the rapid development of economy and society, especially accompanying with the construction of "Shandong exquisite steel base" and other large projects, water supply is becoming more serious. How to maintain the water source of Rizhao reservoir has been paid more attention. Research on geological condition is an important foundation for doing protection and construction work of Rizhao reservoir well.