Abstract: Deep-excavated foundation engineering is common in Beijing area, while the related monitoring and theoretical researches are not quite sound. Through the monitoring and research on bolt pulling force in the supporting project of foundation pit at Land No. 4 Group C, Wangjing Al District, it is deducible that the project is quite distinctive as the pulling force changing tendency of the two lines of bolts are opposite. That reflects in some degree the incompleteness of the current regulations and the strong geographical characteristics of excavation projects. Pile body's displacement monitoring should be introduced to projects so to ensure their safety and to provide detailed data for design optimization and cost reduction. It's recommended that when pulling machinery in construction is available, axial force meter of bolt should be used firstly to quantify the pre-stressing loss locked, and optimize the construction parameter properly in accordance. Therefore, it follows that there exists vast room for optimization for the current excavated foundation engineering. The research result could also provide reference and foundation for similar engineering design.