Abstract: Based on existing experimental data and energy variation principle, generalized variational principle is used to analyse welded turnout structures of railway, and a new method for calculating welded turnout structures is presented. In the model, sleepers are regarded as finite long beams on continuous elastic foundation base, and the relation between rail forces and sleeper displacements is established by analysis of sleeper forces. The energy of welded turnout structures is computed based on assumed longitudinal displacement function of rail. By means of generalized variational methods, the equilibrium equation is derived. The additional temperature forces and the expanding and contracting displacements of the inner rails are analysed. This paper opens a new avenue for welded turnout calculation theory and design method.