Throughthe analysis of factors affecting the hydrochemical characteristics of various water bodies in the reservoir area of Taishan Pumped Storage Power Station in Shandong Province from 2009 to 2020, this study discussed the tracing function of hydrochemical characteristics variation in detecting the water leakage. The results showed that the reservoir water and groundwater of Taishan Pumped Storage Power Station are weakly alkaline, the hydrochemical types are mainly HCO3-Ca, and some are HCO3-SO4-Ca, HCO3-SO4-Ca-Mg and SO4-Ca-Mg, while the chemical types of surface water in Bashangou are SO4-Ca and SO4-Ca-Mg. The ion ratio analysis shows that the weathering of silicate rock is the main source of chemical ions in the reservoir water, the groundwater and the surface water of Bashangou. The surface water of Bashangou is controlled by the rock weathering and atmospheric precipitation at the same time, and the atmospheric precipitation without sufficient water-rock reaction is mixed in. The hydrochemical cluster analysis shows that the water samples of the drainage gallery on the right bank and the measuring weir behind the dam come from the leakage supply of the reservoir water, and the water sources of the measuring weir in the gallery at the bottom of the reservoir, the B2 high-pressure branch gallery, the NO.6 and No.1 construction adits are from the regional groundwater. The results of hydrochemical analysis are consistent with the results of hydrogen and oxygen isotope analysis of water body.