Aiming at the short distance overlapped tunnel in silt reclamation stratum, this paper explored the ef- fects of the construction of the new shield tunnel on the surrounding environment by the 3D finite element soft- ware PLAXIS. The construction generated 14mm moving up for the existing tunnel, resulting in 69mm of surface settlement, which can not meet the deformation control of shield construction. In order to effectively control the impact of shield construction on the surrounding environment, the silt reclamation stratum must be reinforced. Then, the effects of different reinforcement range on the additional deformation of the tunnel were analyzed by 2D finite element method. A specific reinforcement scheme for the silt reclamation stratum was proposed. The silt reclamation stratum within 3m on both sides of the tunnel was reinforced with high-pressure rotary jet grout- ing pile in full depth. It was found that under the condition of reinforcement, the existing tunnel move-up defor- mation and surface settlement can be reduced by 44% and 86% compared with those without reinforcement. The research results show that in the silt reclamation stratum, the reinforcement scheme proposed can effectively control the environmental deformation caused by the tunnel construction and reduce the construction impact.