Abstract: The adsorption heat of toluene on varied decationated mordenites was determined by pulse chromatographic technique. The temperature programmed desorption and reactions were determined by the flowing method.These results show, when the amount of adsorption is less than 5μl/g and the exchange ratio is less than 32%, it is mainly the adsorption properties of Na⁺ site that appears; the adsorption heat is almost independent of the exchange ratio. When the exchange ratio is more than 32%, with increasing exchange ratio, the adsorption on H⁺ site becomes more and more apparent, and the adsorption heat decreases gradually.The curves of specific retention volume vs exchange ratio pass through a maximum when the exchange ratio is within 32-41%. This phenomenon may be related to the decrease of steric effect of the cations in the main channel with the increase of exchange ratio, according to the values of entropy obtained by calculation.