Abstract: Hangzhou Country Garden project is located on the north of Hangzhou XiaSha University Town ecological residential plots, the venue is close to Qian Tang river, which belongs Qian Tang river alluvial and coast plain. In the place which can be influenced by the excavation is the sandy silt with strong permeability, which shows poor stability in the effect of seepage. This project is a large commodity residential covers an area of 65711m², and the construction floor area is 268748m² including 84460m² underground. The plane size of large excavation is 240m×260m and the perimeter is 1000m. The edge length of foundation pit is 360m, and the volume of earthwork is 430000m³.The depth of excavation in large area is 9.5m-11.0m, 13.0m in some local place. It's adopted with 10 new technologies in soil nailing wall support in building industry. Through the scientific management and standardized construction works, creating the achievements which using simple supporting program to complete a huge underground program rapidly and in a high quality.