Based on turnout/bridge interaction principle and finite element method (FEM), an integrated turnout/beam/pier model of jointless turnout on ballasted track was established to analyze the influences of expansion joint on stress and deformation of the turnout. The results are concluded as follows: whether the rail expansion joint is set in front of or behind the turnout, expansion additional force of stock rail will be reduced greatly at the end of the beam; so do the expansion displacement of switch rail and nose rail, the stress of displacement restrictor and spacer block, rail break gap and the longitudinal force of one rail after the other rail broke. But when the expansion joint is set in front of the turnout, the pier’s longitudinal force of continuous beam bridge and the simply supported beam bridge (within the expansion range of the device) increase greatly. When the device is close to the turnout, longitudinal relative displacement of the stock rail to the girder also increases a lot. By comparison, it is more favorable to set the expansion joint behind the turnout, or to set the device at the both ends of the continuous beam, or to set the device at the ends of continuous beam rather than in the center of the span.