In order to study the chemical characteristics and ion source of groundwater and support pollution control and prevention, as well as the rational development and utilization of groundwater resources in Baotou City, 33 groups of groundwater samples were collected from the western area of Kundulun River in Baotou. Piper diagram, Gibbs diagram, ion ratio, and multivariate statistical analysis methods were comprehensively used to analyze the hydrochemical characteristics, ion source and formation mechanism of groundwater. The results showed that the groundwater in the study area was neutral-weak alkaline water, TH was high, and the TDS was between 116~6 032 mg/L, the anions and cations were dominated by SO42-, HCO3- and Na+, Ca2+, Mg2+, and the content of ions in phreatic water was more than that in confined water. The hydrochemistry types of groundwater were complex, the types of anions and cations were dominated by SO4 • Cl, HCO3 • SO4 • Cl, HCO3 and Na•Ca•Mg, Ca•Mg. The chemical components of groundwater were mainly affected by rock weathering leaching and evaporation concentration, followed by cation alternating adsorption and human activities, TDS, total hardness, Ca2+, Mg2+ were mainly derived from the dissolution of silicate rocks and evaporite rocks, K+, Cl-, SO42- were mainly derived from the industrial and mining activities, HCO3-, NO3- were mainly derived from the weathering of carbonate rock and agricultural activities, Na+ were mainly derived from the rock weathering and industrial and mining activities. [ABSTRACT FROM AUTHOR]