The excavation of subway tunnel will induce the extra deformation or even damage of pipelines that lies above. The jointed pipeline was regarded as a beam on elastic foundation. By introducing the equivalent loads to consider the reduction of rigidity at joints， the governing differential equation for the deformation of jointed pipeline was established. Fourier series method was used to solve the governing differential equation. Expressions of the unknown coefficients of Fourier series were derived， and then a set of linear equations for determining relative joint rotations was obtained. Meanwhile， assuming that the soil settlement fits a Peck curve， the settlement of pipeline was computed and compared with that obtained from numerical simulation， which verifies the correctness of the Fourier series method. Results show that， with the loading of soil displacement， the pipeline deforms and rotates largely around its joints. The settlement of soil has small influence on pipe segments beyond 3i (where i is the width of settlement trough)， where joints can be ignored to reduce unknowns because relative joint rotations are far less than the tolerant value. When a joint is located above the excavation center， the soil subsidence can induce the maximum relative rotation at this joint. Therefore， if the locations of joints are unknown， one joint can be set right above the tunnel centerline in order to assure a conservative result.