Abstract: Reconstruction of foundation pits refers to taking measures to reinforce the existing foundation pits to ensure the construction safety of foundation pits and main infrastructures and the surrounding environment without damage. The existing over-service foundation pits are analyzed from the aspects of upper maintenance of foundation pits, anchor reinforcement and construction of three-axis mixing piles in the pits, and puts forward valuable experience is put forward to solve the problems faced by the over-service foundation pits.