This paper briefly introduces Patankar-Spalding Method, which is systematical, active and widely applicable in numerical heat transfer and fluid flow. The corresponding dependent variables, diffusivities and source terms for the general differential equations under all circumstances are explained. By using this method the calculation of two-dimentional Poiseuiue Flow and Couette Flow compared with exact solutions are proved to be high precision. with two-dimentional path-flow in the heat convertor intersification devices as an example, the tilted method is used with FORTRAN 77 programming, and the calculation is done on a SIEMENS 7570c minicomputer.