Antifloating calculation must be made in the design of underground Metro stations. The selection of the calculation parameters and calculation models has great influence on the result of the antifloating calculation. However, so far there is no standard related to the selection of the antifloating calculation parameters, and the attention paid to the displacement of Metro station floors, especially the displacement of floor part within the track scope, is inadequate. In the paper, regarding the antifloating design of a Metro station in Guangzhou, proper calculation parameters and proper calculation formulas are selected, the displacement of the floor of the Metro station is analyzed by means of FEM program and proper antifloating design is determined. The design of the Metro station should not only satisfy the antifloating requirements, but also should satisfy the structural deflection requirements and the service structural displacement requirements. FEM program can be used in the antifloating design of the Metro station.