Abstract: The vapor pyridine adsorption isotherms of coal were investigated using several coals and a model compound(WK11 ion exchange resin and its Na and Ca types) at the temperature of 30℃～60℃. The results indicated that pyridine could disrupt weak hydrogen bonds of original WK11 to form strong pyridine-COOH hydrogen bond, and swell WK11 structure. However, there were a very small amount of adsorption and a very low swelling ratio for Na and Ca type WK11s because of no hydrogen bond formation. There were two different kinds of pyridine adsorption behaviors at low pressure for four coals because of the difference of coal structure. The total pyridine adsorption amount of coals was not only dependent on the hydrogen bonds formed during adsorption process, but also influenced by other kind of specific interaction especially for high rank coals.