A theoretical model based on the elastic foundation beam theory and cavity expansion theory is presented, so as to calculate the vertical displacement of existing underground pipelines. And the transverse isotropic characteristics of the soil are taken into consideration. The solution is then degenerated into isotropic results and is verified by a case study. The multiple factor analysis revealed that: 1) The larger the tunnel’s radius and anisotropic parameters are, the greater the influence on the vertical displacement of the existing pipeline is. 2) The vertical clear distance z0 would have a significant impact on vertical displacement of the underground pipeline when the value of z0 is less than 2.5D. 3) The external diameter and the bending strength of the shield tunnel affect the vertical displacement of the underground pipeline a little.