In order to evaluate groundwater environment for appropriate and sustainable use, impact assessment should be carried out with considering global climate change in future by using groundwater flow and water quality model. In this study, generally used type of two dimensional saturated groundwater flow model and advection-dispersion equation for Total Nitrogen (T-N) are used. Precipitation data is supplied from GCM calculation results (MRI-AGCM3.2s), where single mesh can almost cover study area because spatial resolution of this data is 20km. In consideration of GCM's spatial accuracy and in order to obtain probabilistic estimation from simulation results calculated by a lot of precipitation information, rainfall data surrounding meshes of target area are applied. A risk of groundwater drawdown and water quality deterioration is evaluated with time and space domain by using multiple calculation results. These results are analyzed by using of probabilistic distribution function (PDF).