Based on the deep foundation pit project of the utility tunnel of Yanjiang Avenue in Hangzhou, the HSS model was used for finite element numerical simulation to analyze the deformation of the foundation pit and adjacent pipelines under the dewatering excavation of the foundation pit. The simulation results are in good agreement with the monitoring results, which verifies the rationality of the finite element calculation and parameter selection. Based on the results, an optimized plan for dewatering of the partitioned foundation pit has been proposed, and the deformation response of the foundation pit and adjacent pipelines was studied when the penetration depth of the water-insulating curtain was different under steady-state seepage. The research results show that as the depth of the suspended waterproof curtain increases, the head difference of ground water between the inside and outside of the pit and the peak value of the lateral displacement of the retaining structure increases linearly, and the vertical displacement of the pipeline and the surface settlement outside the pit decrease linearly; Compared with the suspended waterproof curtain, the waterproof curtain has significant advantages in controlling the surface settlement outside the pit and the deformation of adjacent pipelines, however it is more unfavorable for the deformation control of the retaining structure.