A new method for analyzing reactive distillation coupled with membrane separation system was proposed with the viewpoint of non-equilibrium thermodynamics and the phenomenological theory. The synthesis of ethyl tert-butyl ether was chosen as a model system. The synergy of multi-fields such as temperature, concentration and chemical potential in this combined process was discussed, the relationship of each vector within a field was investigated by considering both of Soret effect and Dufour effect. The equations of mass and heat fluxes were established and the coefficients for both of them were obtained with the condition of the synergy in multi-fields. It can be known from the research results that the mass and heat transfer rate were increased or decreased with the synergy of multi-fields; the direction of transfer was also changed by the effect of synergy of multi-fields. From the viewpoint of field synergy, the model of non-equilibrium stage for the reactive distillation coupled with membrane separation was developed. The model incorporated complex reaction kinetics, vapor-liquid non-idealities, distillation and pervaporation process. The rapid solution for this model can be obtained by Newton-Raphson method. Simulation results are in good agreements with the experimental results. (c) 2005 Elsevier B.V. All rights reserved.