<p>Evaluating groundwater quality and its suitability for irrigation is crucial for groundwater environment protection and food security. Irrigating with poor-quality groundwater may impair soil quality, limit the crop categories, and reduce agricultural productivity. In this study, 36 groundwater samples were collected to conduct a comprehensive evaluation of groundwater suitability for irrigation purposes in the Yanggong River Basin of southwestern China. Results showed that the groundwater in the study area was slightly alkaline, predominantly dominated by moderately to very hard-fresh HCO₃-Ca type. Interactions between water and rocks, such as the dissolution of carbonate and silicate minerals and cation exchange processes, dominated the groundwater chemistry. Furthermore, intensive agricultural activities mainly contributed to 18% of the groundwater samples exceeding the standard concerning NO₃^-. The SAR and %Na values indicated excellent to good suitability for irrigation. Most groundwater samples, as shown by the Wilcox diagram, were categorized as appropriate for agricultural use with minimal risk to crops and soils. 21.62% of the EC values classified as doubtful and the result of the USSL diagram suggested potential salinity hazards that require further monitoring and management in the study area. The irrigation water quality index (IWQI) results showed that 86.49% of groundwater samples were classified as good and 13.51% were medium. And the sensitivity analysis confirmed the reliability of the IWQI assessment result. Random froset (RF) model showed a better prediction effect with a strong correlation of 0.9581 and was an alternative water quality prediction model. The findings of this research significantly contribute to the sustainable management of groundwater resources for irrigation purposes in an agriculture-dominant area worldwide.</p>