This article established groundwater flows differential equation mathematical model of Sanjiang Plain on the hydrology theory foundation, and used the analysis finite element method to liner change the differential equation into the large-scale system of linear equations. It took linear equations as a part of constraint conditions of the optimized model, carried on the groundwater flow status equation and the optimized model the coupling, and carries on the solution with the Lingo software. The results indicated that this local shallow layer groundwater resources were rich and have the big development potential. But recent years water resources disposition was unreasonable and ground water mining quantity was oversized, these caused the region water flux to assume the drop tendency.