|Abstract:As one of the most important water sources, groundwater has been significantly affected by human activities. It is of great significance for the rational utilization of groundwater resources to study the chemical characteristics and formation mechanism of groundwater. Various types of aquifers are distributed in in Yinan of East Wenhe River Basin, and agriculture and aquaculture are well-developed. Therefore, this area is an ideal area for the study of formation of groundwater hydrochemistry under the influence of human activities. In this paper, the Piper diagram, ion ratio method and mathematical statistical methods (correlation analysis, factor analysis, cluster analysis) and other methods are used to study the groundwater hydrochemical characteristics and formation mechanism of the study area. The results show that the groundwater hydrochemical types are mainly HCO3-Ca and HCO3-Ca?Mg, and the TDS content is between 243 and 1473 mg/L. The HCO3-, SO42-, Ca2+ and Mg2+ in groundwater mainly come from the dissolution of carbonate minerals and sulfate minerals, while Na+, K+, Cl- and NO3- mainly come from the dissolution of halite and the pollution of human activities. The effect of water-rock interaction on groundwater hydrochemistry exceeds 62.024%. The number of groundwater samples with obvious influence by human activities account for 13.6% of the total groundwater samples, and the contribution of anthropogenic impacts to groundwater hydrochemistry reaches 20.318%. The river valley plain is obviously polluted by human activities such as agriculture and aquaculture.