The adsorption behavior of methane in simulated coal-bed gas on several micropore zeolites is studied. Alkali and steaming treatments of ZSM-5 are carried out in order to adjust the pore structure and to further elucidate the effect of pore structures on methane adsorption behavior. Further, the effect of adsorbed water on ZSM-5 zeolite is also considered. Textural properties of material are characterized by nitrogen adsorption-desorption at 77 K. The results indicate that pore structures of zeolite adsorbent have a more important effect on the adsorption performance, compared with the specific surface area. The presence of adsorbed water on micropore zeolite is unfavorable to the methane adsorption.