文中以揭示鄂尔多斯盆地长武-彬县地区白垩系洛河组地下水水化学场的形成机理为主要研究目的。在了解鄂尔多斯盆地的地形、地势、地貌、新构造运动、岩石类型、岩性构造和其他特征的基础上,运用化学热力学原理、质量作用定律和质量守恒定律,应用水文地球综合分析方法和地下水地球化学模拟技术,对白垩系洛河组地下水进行了水-岩作用的地球化学模拟。应用Phreeqc软件定量分析研究了该区地下水的演化过程、形成机理,总结了矿物或次生矿物的溶解沉淀规律以及水溶液中化学成分的变化,主要结论为:1)在水流模拟路径上主要发生了方解石与伊利石的沉淀和白云石、石膏、岩盐、斜长石、钾长石和钾云母的溶解,以及Ca-Na2间的阳离子交换作用;2)在水D20点南附近可能是洛河含水岩组地下水的排泄基点。结果表明水-岩作用模拟结果有助于揭示研究区地下水化学环境的演化机制。 The main purpose of this paper is to reveal the formation mechanism of groundwater hydrochemical field of Cretaceous Luohe Formation in Changwu-Binxian area, Ordos Basin. On the basis of understanding the topography, topography, geomorphology, neotectonic movement, rock type, lithology structure and other characteristics of the Ordos Basin, applying the principle of chemical thermodynamics, the law of mass action and the law of mass conservation, Chemical simulation technique, a geochemical simulation of water-rock interaction was carried out in the Cretaceous Luohe Formation. Phreeqc software was used to quantitatively analyze the evolution process and formation mechanism of groundwater in this area. The law of dissolution and sedimentation of mineral or secondary minerals and the chemical composition in aqueous solution were summarized. The main conclusions are as follows: 1) Precipitation of calcite and illite and dissolution of dolomite, gypsum, rock salt, plagioclase, potassium feldspar and potassium mica, and cation exchange between Ca and Na2; 2) Group groundwater drainage base point. The results show that the simulation results of water-rock interaction are helpful to reveal the evolution mechanism of groundwater chemical environment in the study area.