The cutting of the foundation pit of a Tshaped transfer Metro station will have unbalanced pressure on the existing Metro structure. In the paper, numerical analysis is made on the deformation of the existing Metro structure caused by the cutting of the foundation pit of a Tshaped transfer Metro station by means of Plaxis finite element program, so as to protect the existing Metro structure and to ensure that the deformation of the existing structure can meet the operation requirements. The study, which shows that open cutting can be adopted for the foundation pit of the Tshaped transfer Metro station, can provide theoretical reference for the construction drawing design in the following stage. Furthermore, a series of countermeasures are proposed for the cutting of the foundation pit and the dismantling of the existing structure.