Abstract: With the acceleration of urbanization, ultra-deep foundation pit projects have raised higher demands for the efficient utilization of land resources. Based on the case of the ultra-deep foundation pit project of Line 8 at Xiawafang Station in Tianjin, this study analyzs the influence of the ultra-deep metro foundation pit project on the deformation of the adjacent existing subways. The results show that: ① The track and structure of Line 1 (0.38 m away from the foundation pit) have relatively large deformation, which is manifested as first rising and then falling or settling. However, Line 5, being farther away from the foundation pit (44.3 m), has less deformation, but the overall difference is not significant. ② The coordinated development of the horizontal displacement of the station structure and the foundation pit wall, as well as the settlement of the ground surface and the tunnel structure, shows significant spatiotemporal characteristics. During the shallow excavation stage (H < 10 m), the growth rate of the horizontal displacement of the soil near the foundation pit wall is approximately 1.18 times that of the existing tunnel structure. The surface settlement is slightly faster than that of the tunnel structure with a lag of about 14 days. During the deep excavation stage (H≥10 m), the growth rate of the horizontal displacement of the soil near the foundation pit wall increases significantly, reaching 20 times that of the existing tunnel structure, and the growth rate of surface settlement is 6.37 times that of the tunnel structure. The spatio-temporal differences increase significantly. ③ The ratio Ω of the horizontal displacement of the station structure to the displacement of the soil at the same depth fluctuates between 0.083 and 1.080, and the ratio θ of the structure settlement to the surface settlement varies between -0.086 and 0.502. Both show obvious spatiotemporal characteristics. Therefore, the deformation of the existing station structure can be approximately predicted through the trends of the lateral displacement of the foundation pit wall and the surface settlement.