Abstract: Wujiazhuang Reservoir is located in Licheng County of Shanxi Province. It was designed to be constructed on Zhuozhang River confluent of the southwest basin and north basin. Its total capacity is 360 mullion cubic meters and will be a large-scale hydroelectric project. The bedrocks at the dam site are hard quartz sandstone of Chuanlinggou Formation of Sinian system and the Cambrian and Ordovician carbonate rocks. Cover more than 50% of the total reservoir area. The karstic leakage is a most significant engineering geological problem. It can directly affect the reservoir site and the feasibility of project. This paper presents a corresponding analysis and an evaluation of the condition and then a recommendation of the rexervoir sizes and capacity.