Microporous N‐containing activated carbon (N‐CAC) suitable for hydrogen sulfide adsorption was prepared by impregnating raw activated carbon with a 25% methylol melamine urea solution and then heating it at different temperatures from 100 to 1000°C. The structures of raw activated carbon and N‐CAC Ho. 8 carbonized at the most suitable temperature 850°C have been discussed based on applying the Dubinin‐Radushkevich equation to adsorption isotherm of hydrogen sulfide. The 12.2% increase in micropore volume of N‐CAC No. 8 result from the numerical increase of micropores rather than radial expansion of micropores. The relation of q and AS could be consistently explained by the interaction of hydrogen sulfide with micropores of adsorbents.