The integral interpolation method and Monte-Carlo stochastic method are adopted to study groundwater flow problems theoretically, and the Monte-Carlo Stochastic Difference Method (M.C.S.D.M.) is also developed.The calculating patterns and treatments of boundary conditions for the two kinds of methods are deduced and analyzed; For a two-dimension confined stable groundwater flow mathematical model.We compared its analytical solutions with the results of M.C.S.D.M.They concide very well.