The irreversibility of ferroelectric phase transition has been studied by using irreversible thermodynamics.Heat stagnation of the first-order ferroelectric phase transition and polydomain configuration of ferroelectrics can be explained on the basis of the principle of minimum entropy production.A conclusion has been derived that the heat stagnation is not an intrinsic property of a system in which a first-order ferroelectric phase transition arises.The finiteness of the system's surface is connected with the heat stagnation.