摘要： Analysis of environmental significance and hydrochemical characteristics of river water in mountainous regions is vital for ensuring water security. In this study, we collected a total of 164 water samples in the western region of the Altay Mountains, China, in 2021. We used principal component analysis and enrichment factor analysis to examine the chemical properties and spatiotemporal variations of major ions (including F–, Cl–, NO3–, SO42–, Li+, Na+, NH4+, K+, Mg2+, and Ca2+) present in river water, as well as to identify the factors influencing these variations. Additionally, we assessed the suitability of river water for drinking and irrigation purposes based on the total dissolved solids, soluble sodium percentage, sodium adsorption ratio, and total hardness. Results revealed that river water had an alkaline aquatic environment with a mean pH value of 8.00. The mean ion concentration was ranked as follows: Ca2+>SO42–>Na+>NO3–>Mg2+>K+>Cl–>F–>NH4+>Li+. Ca2+, SO42–, Na+, and NO3– occupied 83% of the total ion concentration. In addition, compared with other seasons, the spatial variation of the ion concentration in spring was obvious. An analysis of the sources of major ions revealed that these ions originated mainly from carbonate dissolution and silicate weathering. The recharge impact of precipitation and snowmelt merely influenced the concentration of Cl–, NO3–, SO42–, Ca2+, and Na+. Overall, river water was in pristine condition in terms of quality and was suitable for both irrigation and drinking. This study provides a scientific basis for sustainable management of water quality in rivers of the Altay Mountains.