Due to its high chemical stability,good thermal resis ta nce, ideal conductivity and ion-selective permeability, Nafion membrane has bee n 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 permeat ion of organic compounds through the membrane were seldom reported in literature .3-methylpyridine is the main raw material for electrochemical synthesis of nia cin.In this work, the permeating fluxes of 3-methylpyridine were measured in th e H 2SO 4 aqueous solution at different concentrations and temperatures.The re sults showed that the permeating flux was directly proportional to the molar con centration of 3-methylpyridine at a given temperature.The relationship between the natural logarithm of proportional coefficient and the reciprocal of temperat ure was linear.The Arrhenius equation for the relationship between permeating fl ux 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.