Abstract: The excavation of group foundation pits will change the stress state of the surrounding soil and result in deformation and displacement of the existing adjacent metro tunnels. The excessive settlements may induce the crack of tunnel segments and eventually may affect the safety operation of metro trains. Sine the influence is complicated, automatic monitoring is important for safe operation of metro tunnels. The effects on the existing adjacent metro tunnels during excavation are simulated through three-dimensional numerical analysis, and the displacement of the tunnels is qualitatively analyzed. Based on these analyses, an automatic monitoring system including composition, surveying rules, surveying area, instrumentation location, surveying precision and surveying effect on monitoring deformation of the existing adjacent metro tunnels is introduced. Combing the three-dimensional numerical analysis with the automatic monitoring may provide certain basis for rational use of protective measures for metro tunnels influenced by adjacent excavation.