With the intensifying development density of urban underground space in China，the impact of ultra-large foundation pit construction on the normal operation of adjacent structures cannot be ignored.Relying on the Huangmugang Comprehensive Transportation Hub Project in Shenzhen，this paper studied the deformation of the envelope structure and soil caused by the excavation of the ultra-large special-shaped foundation pit，as well as the structural response of the deformation of the adjacent existing station and the temporary steel bridge.The paper optimized the construction scheme of the special-shaped foundation pit excavation.The results show that the deformation trend of the envelope structure on the north and south sides of the foundation pit is the same as a whole，but the deformation at the external corner on the north side is large.The envelope structure of the existing station as a whole is displaced into the pit，with a maximum horizontal displacement of 9.4 mm，and the horizontal displacement of the steel box girder bridge pile after excavation of the foundation pit is large，with the maximum value reaching 10.5 mm.The overall construction safety is ensured by adding temporary concrete supports on the lower ground and adding steel sleeves on the piers of the temporary steel bridge in the pit.