Abstract：In this study, the authors investigated the hydro-chemical features and distribution of predominant constituents and ions in the groundwater of western Hetao Plain, Inner Mongolia, based on field survey and analyses of 400 water samples. The results indicate that the groundwater quality is generally not satisfactory because the densities of As, Cl-, SO2-4, TDS, total hardness, F- and Fe are in excess of the standard levels. Hydrochemical types in the study area are mostly Cl-HCO3-Na, Cl-Na, and HCO3-Cl-Na. Predominant components such as As, P, Fe, Cl-, F-and SO2-4 are distributed along the boundary of the alluvial and proluvial fans in the northwest of the study area and the alluvial plain with lower topography as well as Langshan Town in northern Linhe area. Furthermore, this study presents the correlations of all the 14 tested constituents based on methods of correlation analysis and multi-variable linear regression. It is shown that the relations between P, Fe and As are significant.