The elastic foundation beam method is the main method of stress analysis of the supporting structure of the foundation pit, it can easily calculate the internal forces and displacement of the structure, however, the computing method of elastic foundation beam deflection equation is more complicated. So according to the computation principle and method of elastic foundation beam, a computing program has been programmed by MATLAB mathematical software. The program has been applied to compute the internal force and deformation of deep foundation pit of Suzhou subway station. The variation law of displacement and bending moment of supporting structure during excavation has been obtained. The results of the measured and calculated agree well, and the computing results have efficiently guided and optimized supporting design.