In order to achieve the ideal outcome and accuracy in the structural design of Metro stations, the author calculates the internal force of the longitudinal beams of two types of Metro stations, i.e., the singlecolumn twospan ones and the doublecolumn triplespan ones, by the traditional 2D simplified calculation method and the 3D finite element analysis method respectively. The analysis indicates that the difference in the internal forces calculated by these two methods has a regular pattern. The author proposes that the traditional 2D simplified calculation method be further used and the calculations be modified so that the results can better accord with the actual loading conditions of the structures.