Wutongshan tunnel of Jichang Road project in Xiamen, China, which crosses underneath No. 34 building, is constructed by CRD method. The construction procedure of the tunnel is optimized by engineering analogy method. The settlement rule of the existing building is analyzed by numerical analysis method. Assistant construction measures, such as advance grouting, surface concrete paving, compensation grouting, fullface curtain grouting and advance reinforcement by large pipe roof, are proposed on basis of the measured settlement values and simulated settlement values. In the end, the settlement of the building caused by tunnel construction is effectively controlled, with the final settlement being less than 40mm.