Geochemical modeling of ground water is an effective method in evaluatingground water quality, simulating water-rock interaction, understanding the formof migration of pollutants and features of their variation when ground water-rockinteraction occurs and predicting the chemical evolution of ground water. In thispaper, the basic theory of geochemical modeling of ground water is summarized,and the method of speciation calculation, mass balance reaction model and reactionpath simulation in geochemical modeling of groundwater are also discussed.Finally,this paper points out the deficiency and developmental trend of geochemical model-ing of groundwater.