Abstract: In the construction process of deep foundation pits, the passive zone improvement at the pit bottom is often used to control the deformation. But the study on the passive zone improvement at the excavation section of deep foundation pits is very rare. The displacement control effect of the passive zone improvement at excavation section is studied. The results show that the optimal improvement height for the passive zone improvement exists. When the improvement height is lower than the optimal height, the horizontal displacement of the retaining wall and the settlement of the ground surface settlement reduce with the increase of the improvement height. When the improvement height is higher than the optimal height, the maximum of the above-mentioned two remains almost unchanged. But the increase of the improvement height can reduce the horizontal displacement of the top of the retaining wall, which has great significance for the protection of the surrounding environment.