With the development of underground space in urban construction, the number of deep foundation pit supporting projects is increasing. During the excavation of deep foundation pit, the unloading would cause the stress-strain effect of rock and soil, and then induce the deformation of surrounding buildings foundation. Due to the limitation of construction site, the foundation of tower crane has to be placed on the edge of deep foundation pit retaining structure. The operation load of tower crane structure will cause hidden danger to the safety of foundation pit. Therefore, before the foundation pit excavation, it is necessary to reinforce the tower crane foundation and predict the deformation characteristics of the tower crane foundation during the construction process. First of all, based on the conditions of engineering geology and construction environment, this project has designed the anchor pulling pile support scheme to reinforce the tower crane foundation and foundation pit retaining structure. Then, the finite element model of the whole process of foundation pit excavation was established through Midas GTX NX software, and the deformation characteristics before and after the reinforcement of tower crane foundation were simulated. Finally, the numerical simulation results were compared with the field monitoring data in the excavation process to evaluate the reliability of the tower crane foundation reinforcement design scheme. The study shows that the reinforcement design of this project has a good effect on the deformation control of the tower crane foundation. The study results will provide reference for similar deep foundation pit support design and construction.