[Objective] In order to reveal the hydrochemical characterization of groundwater and provide a theoretical basis for the rational exploitation of groundwater resources, the hydrochemical characteristics and irrigation suitability of groundwater in Jianyang City of Sichuan Province were analyzed and evaluated.[Methods] Some research methods such as Gibbs plot, molar ratios and other statistical analysis were employed to study the hydrochemical characterization of groundwater in this area. Combining the entropy weight theory with the fuzzy matter-element method, the fuzzy matter-element model based on entropy weight is established by using Matlab to evaluate the groundwater quality comprehensively.[Results] The results indicate that groundwater in the study area is fresh water for shallow aquifers and brackish water for middle-deep aquifers. The shallow groundwater was dominated by the HCO₃-Ca and HCO₃-Ca·Mg types, and the middle-deep groundwater was dominated by the HCO₃-Na·Ca, HCO₃·SO₄-Ca·Mg, SO₄-Na·Ca types. The groundwater in the study area was primarily controlled by weathering of rocks, including the dissolution of minerals(halite, calcite, gypsum and silicate) and ion-exchange adsorption. The shallow groundwater was primarily affected by human activities, and the middle-deep groundwater was affected by mixing from deep brine.[Conclusion] The results of comprehensive evaluation of water quality show that the shallow groundwater is suitable for agricultural irrigation, but the middle-deep groundwater is not suitable for agricultural irrigation in the long run. The groundwater quality gradually become worse from shallow aquifers to middle-deep aquifers.