Study is made on site testing and numerical simulation, so as to guarantee the safety of the running Metro line and to analyze the deformation behaviors of Metro station and joint between shield tunnel and Metro station under the condition of communal underground diaphragm wall between deep foundation pit and Metro station in Shanghai area. The vertical displacements of Metro station and shield tunnel are analyzed. The influence of excavation depth and relative position of foundation pit on Metro station and joint between shield tunnel and Metro station are analyzed by means of 3D numerical model. The behaviors of curvature radius and relative bending of joint between shield tunnel and Metro station are discussed; and the safety of the joint between shield tunnel and Metro station is estimated. The testing results and numerical simulation results show that: 1) The deformation of joint between shield tunnel and Metro station is serious. 2) The curvature radius of joint between shield tunnel and Metro station decreases with the excavation depth of foundation pit increases; and the relative bending increases with the excavation depth of foundation pit increases. 3) The curvature radius of joint between shield tunnel and Metro station at the total connection section between Metro station and foundation pit is large.