Assuming phenomenological thermal flow balance and solute conservation, a numerical model was proposed for recalescence in bulk undercooled alloy. During the calculation, the evolution of residual melt temperature and concentration is solved as function of the transformed solid fraction. After quantitative thermodynamic calculations, a transition from non-equilibrium to equilibrium process can be described by the change of liquid/solid Gibbs energy difference. The proposed model has been applied to Cu-Ni solid solution and Fe-B hypereutectic alloy. The predicted post-recalescence temperature TR agrees well with the experimental results.