Abstract：Groundwater controlling is the critical step in design and construction of deep excavation. Effect of the groundwater on deep excavation is discussed briefly，and fundamental treating method is put forward. Taking Baofeng Times Square deep excavation as an example，effect of the deep-well dewatering on supporting structure and surroundings is analysed. Monitoring data show that deformation of the retaining structure and surrounding buildings developed rapidly during excavation. When earthwork is finished，the supporting structure tends to be stable，but surrounding buildings subside continually because of dewatering. Not only dewatering but also the foundation form and height of the surrounding buildings will influence their own settlement.
