In order to reveal the hydrochemical characteristics and evolution law of groundwater in Baoding Plain, this paper takes Baoding Plain as the research object, and analyzes the hydrochemical characteristics of 216 groups of groundwater samples. Methods: This paper used Piper triplot, Gibbs plot, correlation ion analysis methods to study the chemical composition and spatial distribution characteristics and water chemical types of deep and shallow groundwater in Baoding Plain. The formation mechanism and control of water chemistry were identified, and the causes of water chemical evolution were analyzed on this basis. Results: The results are as follows. Along the direction of groundwater runoff, the content of main ions in shallow groundwater and deep groundwater showed an obvious gradient law. TDS, Na+, Mg2+, Cl-, SO2-4 and HCO-3contents gradually increased, while K+and Ca2+ gradually decreased. The dominant cation Ca2+ was gradually replaced by Na+, and the dominant anion HCO-3 gradually shifted to Cl-. The chemical characteristics of groundwater are mainly affected by water—rock interaction, alternating cation adsorption and human activities. Conclusions：The water—rock interaction is mainly caused by the co- filtration of carbonate rocks and aluminosilicate rocks. The shallow groundwater greatly affected by human activities is concentrated in the recharge area, and NO-3 is the main ion affected. It is related to agricultural activities and strong permeability of Coarser lithologic particles in Piedmont alluvial plain.