In order to understand the hydrochemical characteristics of groundwater and the main sources of ions in area along the Yellow River in Henan Province, five typical profiles were selected along the flow direction of the Yellow River in its midstream, transition, and downstream sections, a total of 14 monitoring points were laid out, and three samples were collected in 2023. Mathematical statistical analysis, ion ratio diagram, Piper diagram, and Gibbs diagram were used to analyze the hydrochemical characteristics of the study area, and the factors affecting the hydrochemical composition were discussed. The results show that the dominant anion in the study area is HCO-₃, the main cations are Na⁺ and Ca²⁺, and the pH value of groundwater is in the range of 6.02 to 7.75, demonstrating that groundwater in the study area is between weak acidity and weak alkaline and it belongs to low salinity water. The main types of groundwater hydrochemistry in five typical profiles from the middle reaches to the lower reaches of the Yellow River are HCO₃-Na type, HCO₃-Na·Ca type, HCO₃-Na·Ca and HCO₃·SO₄-Na·Ca·Mg types, HCO₃-Na·Ca and HCO₃·Cl-Na·Ca·Mg types as well as HCO₃-Na·Ca and HCO₃-Na·Ca·Mg types. The hydrochemical composition of groundwater in the study area is mainly affected by water-rock action and evaporation concentration, and ion exchange is an important factor for relative abundance of Na⁺ in regional groundwater.Compared with agricultural activities, industrial and mining activities have a greater impact on the hydrochemical composition of groundwater in some study areas. The influence of human activities on the chemical composition of groundwater gradually increases along the flow direction of the Yellow River.