Abstract: Due to its high chemical stability,good thermal resistance, ideal conductivity and ion-selective permeability, Nafion membrane has been used in many electrochemical systems.The significant progress has been made in the applied research of Nafion membranes in fuel cell, membrane separation and organic electro-synthesis.For organic electro-synthesis,the studies on permeation of organic compounds through the membrane were seldom reported in literature.3-methylpyridine is the main raw material for electrochemical synthesis of niacin.In this work, the permeating fluxes of 3-methylpyridine were measured in the H₂SO₄ aqueous solution at different concentrations and temperatures.The results showed that the permeating flux was directly proportional to the molar concentration of 3-methylpyridine at a given temperature.The relationship between the natural logarithm of proportional coefficient and the reciprocal of temperature was linear.The Arrhenius equation for the relationship between permeating flux and temperature was obtained.The apparent activation energy and apparent pre-exponential factor were estimated as 63.3 kJ•mol^-1 and 2.69×108 m•h^-1.