Abstract: By analyzing the monitoring data of an underground deep foundation pit at Xintang Road-Jingfang Road cross of Hangzhou metro, including horizontal displacement of diaphragm wall, axial force of steel bracing, ground settlement and groundwater fluctuation etc., some valuable conclusions and suggestions are obtained. It is shown that the horizontal displacement of soils is one of the most important reasons that lead to that of wall. The difference between the monitoring data of different walls is concerned with the soil texture. The degree of ground settlement and the horizontal displacement are closely related. Unusual change of the groundwater in foundation pit always results in subsidence of neighboring ground. Before excavation, the axial force of steel bracing should be paid more attention to, and the horizontal displacement should be monitored after excavation. The increasing frequency of monitoring axial force is a good way to ensure construction safety.