Abstract: The excavation of the deep foundation pit adjacent to the subway line has an impact on existing subway tunnels. We take a deep foundation pit project in Beijing central area as an example. In the paper, We simulate the influence of adjacent subway tunnel caused by excavation of deep foundation pit with FLAC3D.We also evaluate the deformation control of subway tunnel and puts forward relevant monitoring suggestions. The maximum deformation value of the tunnel structure is less than 3.00mm. And the early warning value of tunnel structural deformation is 2.10mm, and the alarm value is 2.40mm during construction.