The interval tunnel of Ningbo metro line 2 goes through the site of a car showroom project. By FEM analysis, the internal force of the tunnel is calculated under the ground upper load. From the engineering planning of the two projects, the time interval of the two projects is about six months to twelve months. When the interval tunnel begins to construct, the settlement of the foundation of the showroom is still not finished. By the analysis of consolidation rate of soil, the additional settlement of tunnel caused by the latter settlement of the showroom building is analyzed. And the safety of the tunnel is evaluated according to the analysis.