Abstract: In the construction process of metro tunnel, to special attention should be paid the problem of excavation disturbance affecting the adjacent piles of buildings and bridges. Xianggong Station of Dalian metro line No. 2 adopts the open excavation method. There is only a distance of 2.55 m between the trestle bridge pile and the external wall of main metro structure. How the tunnel excavation and supporting affect the trestle bridge is studied by means of numerical simulation. The displacements of ground strata, the maximum stresses and the displacements of skirt pipes and bridge piles are obtained. Based on the numerical simulation, by adopting the orthogonal method and the extreme difference method, the influences of six factors of E₂, μ₂, E₃, μ₃, c₃ and φ₃ on the settlements of ground surface and bridge pier, leanings of skirt pipes and bridge piles and supporting force are analyzed, and the sensitivity sequence of the factors is obtained. The analysis results have active meaning for the feedback analysis and construction scheme appraisement.