|Abstract:To examine the hydrochemical characteristics and evolution patterns of regional groundwater system under the influence of climate change and human activies, it plays an important role in revealing groundwater cycle changes, water resource safety and management, and regional eco-environmental conservation. In this study, We analyzed and compared the hydrochemical characteristics and spatial distribution between surface water and groundwater, and investigated the hydrochemical evolution and zoning patterns of groundwater system in Baiyangdian Wetland, North China Plain. The results show that hydrochemistry of both surface water and groundwater has a significant spatial variation characteristics. Hydrochemical characteristics and hydrodynamic condition of river water largely control the hydrochemical types and evolution of wetlands and shallow groundwater. Wetlands water in Zhaozai, Songzhuang and Liutong has low TDS, which have good hydraulic connection with inflow river of Puhe, Fuhe and Baigou, and the hydrochemical facies are of HCO3-Ca·Na·Mg, HCO3·Cl-Na·Ca, HCO3·Cl-Na·Mg·Ca water types. Alone flow paths from north to south, the major hydrochemical types of wetland water change from HCO3·Cl-Na·Mg to HCO3·Cl-Na type in the southern wetlands, due to the intense evaporation. Wetland chemical evolution is mainly controlled by evaporation, cation exchange processes and calcite precipitation. The major hydrochemical facies of shallow groundwater are HCO3-Mg?Na, HCO3-Na?Mg type, while it is dominated by the Cl?HCO3-Na?Mg, Cl?HCO3-Ca?Mg?Na water type in the areas seriously affected by human activities. In the local groundwater depression area, groundwater belongs to the HCO3·SO4-Na, HCO3·SO4·Cl-Na, SO4·HCO3-Na·Mg, SO4-Na water types, which is closely related to anthropogenic activities and saline water mixing effect drived from groundwater overflow recharge. The shallow groundwater system of Baiyangdian Wetland was characterized by hydrochemical zoning evolution patterns, which was divided into seven subzone system. The major ions inⅠ?Ⅳ suzones were mainly derived from the dissolution of carbonate, evaporite and silicate mineral weathering dissolution, characterized by good water quality and low TDS values. The groundwater evolution was primarily controlled by water-rock interaction, evaporation, cation exchange and calcite precipitation. The shallow groundwater subzone system of Ⅴ?Ⅶ in the southwest wetlands and the lower reaches had been influenced by human activities, the major ions were the most attributed to evaporite, silicate weathering dissolution and contamination inputs from anthropogenic activities. Evaporation concentration, mixing effect, calcite precipitation and cation exchange are the main factors in controlling the groundwater evolution process.