Abstract: Because of the complexity of ambience, in the construction of city subway, foundation pit excavation can cause disturbance to the soil, and bring damage to the building and underground pipe, even the stability of foundation pit can be lost. Based on the project of Shenzhen metro,introduced the design and construction of the deep foundation pit,discussed the monitoring scheme of foundation pit excavation, also analyzed and summarized the monitoring result. Project example shows that choosing reasonable monitoring scheme and carrying out real-time dynamic control to environment and retaining structure ensured the safety of the excavation process.