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 researches on pulling force of bolts in the supporting project of foundation pit at Land No. 4 Group C, Wangjing A1 District, it is deducible that the project is quite distinctive as the change tendency of pulling force of the two lines of bolts are opposite. It is reflected by the incompleteness of the current regulations and the strong geographical characteristics of excavation projects. The displacement monitoring of piles should be introduced into the project so to ensure its safety and to provide detailed data for its design optimization and cost reduction. It’s recommended that when the pulling machines in construction are available, axial force meters of bolts should be used firstly to quantify the pre-stressing loss locked so as to optimize the construction parameters properly in accordance. Therefore, it follows that there exists vast room for the optimization for the current excavated foundation engineering. The research results may provide reference and foundation for similar engineering design.