With the expansion of the construction scale of urban building basement, the technical requirements of excavation and support of deep foundation pit are higher. Based on an engineering example, this paper expounds the construction scheme of deep foundation pit excavation and support in a residential area project. It introduces the construction methods of soil nailing wall support in the north side of the foundation pit, retaining row pile support in the east side and inter pile wall engineering construction. It analyzes the method of controlling measurement error in the process of steel casing burying, and the technical problem that the reinforcement cage does not jam in the process of large diameter long pile construction. In this paper, the key points of quality control in the construction of deep foundation pit support are discussed and summarized to ensure the smooth progress of the project. The research results provide references for other similar projects.