Abstract: The requirements of underground subway station construction have become more complicated with the effects of, and requirements regarding, existing buildings and complex environments. The Pile-Beam-Arch (PBA) method is widely used in light of the advantages of safety and decreased impact on the environment under complex building conditions. However, the construction mechanical behavior of the PBA method is very complicated, and there are some differences between the internal forces predicted by traditional load-structure design models and the actual forces, which may result in inappropriate structure design if using the common load-structure model for a PBA subway station. Based on a station project of the Beijing metro, this paper carries out a model experimental study and numerical simulation for the mechanical behavior of the PBA method, which reveals internal force variations for the middle column, side pile and crown during the construction process, leading to a proposed modified load-structure model for mechanical analysis of the subway station by the PBA method.