Abstract: Relying on the underground passage of a commercial plaza in a coastal city that passes through the existing road project, the finite element analysis method is used to analyze the influences of the surface deformation caused by the excavation of the underpass and the change of the internal force of the supporting structure. The calculation results show that the overall safety factor of the secondary lining support of the tunnel meets the requirements of the specification except that the safety factor at a few nodes does not meet the requirements of the specification. The maximum displacement of the underground passage is-32.2mm at the inverted arch of the tunnel centerline. Therefore, when the underground passage is excavated, it is necessary to timely support and implement the inverted arch, and the appropriate time should be selected to remove the lining, so as to avoid the safety problems caused by excessive settlement.