Abstract: The first-stage MTR property project of Longxiang station of Hangzhou Metro Line 1 is located in the downtown of Hangzhou, which is close to the Longxiang station under construction at its east and to Huansha Canal at its west. The environment of the project is very complex. At the same time, the original site of the MTR property project is the Union Building’s basement whose piles and retaining piles intersect with the three-storey basement of the project. Because of the particular position of deep soft soils and a large number of nearby facilities to be secured, it is important to optimize bracing projects for deep excavation of the project, especially in the case that the original basement can not be cleaned. The problem due to the existing basement is solved successfully by grooving the floor to set up the guide wall of diaphragm wall and dismantling the existing basement gradually to coordinate the formation of the supporting systems. The excavation is carried out smoothly, and the safety of the surroundings is ensured.