Settlements and deformations of soils induced by shield tunneling have adverse impact on adjacent underground pipelines, especially large settlements and deformations. The unified solution of vertical displacements of soil movement model is adopted to calculate soil free displacements induced by shield tunneling. The variation control equation is established by energy method. And then a calculation method of vertical displacements of underground pipelines induced by shield tunneling is obtained and put into comparison with LIU Xiaoqiang Method and field test. Meanwhile, the influence of soil condition and buried depth and material of underground pipeline on vertical displacement of underground pipeline is analyzed. The analytical results show that: 1) Compared to LIU Xiaoqiang Method, the results of energy variational calculus based on unified solution coincide with the actual condition better. 2) The vertical displacement of pipelines induced by doubletrack shield tunneling is asymmetrical along the central axis of two tunnels. 3) The soil conditions have significant impact on vertical displacement and width of settlement trough of pipeline, while the buried depth and material of pipeline have little impact.