Abstract: It is introduced that the calculating principle and the math model of the equilibrium constant method for calculating the equilibrium distribution of species of water solution.Based on this,the paper discusses the application of computerized aqueous chemical model in environmental evaluation of groundwater by taking the flyash landfill area of Hancheng Power Plant as an example.It can be seen that more information can be got using the computerized aqueous chemical model instead of the traditional water chemical method.This will be great helpful for the understanding and mastering of the chemical characteristics and the chemical reaction of groundwater in relation to the environment it is in.