Abstract: The excavation of the eastern section of Slender West Lake tunnel is a typical long-narrow one and the excavation depth varies greatly. As a major urban planning project in Yangzhou, this project has a strict time limit. Several retaining systems are adopted considering the excavation depth in different districts. As the excavation depth increases, this excavation adopts diaphragm walls, cast-in-situ bored piles and waterproof curtains, SMW piles, soil-cement retaining walls and slope excavation in turn. The design of excavation supporting system has provided convenience for its safety, saved the cost and also guaranteed the construction period of the whole project.