The foundation pit of Mingji hospital in Nanjing is located in the protection scope of the operating Metro system. During the excavation of the foundation pit, settlement monitoring points are arranged in the Metro tunnels, automatic monitoring system is established and EL beam automatic monitoring is executed. The monitoring practice shows that, due to the application of EL beam automatic monitoring, the manpower, materials and cost needed for the monitoring are reduced and the safety of the monitoring personnel is guaranteed. 