In order to study whether test field affect surrounding underground water or not, the paper used the Galerkin finite element method to establish shallow groundwater flow model of test field and used Fortran language to program to flow model and carried on numerical simulation to test field underground water. The calculation is divided into twelve stages, the time step of each stage is 30days. The calculation results show that in the model recognition phase and confirmatory phase, all of the observation hole water head are calculated and measured, relative error rates are 66.28% and 88.53% in each period , the model can be used to conduct site groundwater flow calculation. The level of groundwater in surrounding area increases 94.08mm, test project after completion can affect the surrounding field.