Pilot preparation was carried out for activated carbon from petroleum coke/KOH chemical activation, to improve the methane storage capacity. The effects of activation temperature in the range from 973 to 1073 K and particle size from 0.10 to 0.45 mm were studied by nitrogen adsorption isotherms and scan electronic microscopy. It was found the activation temperature significantly influenced the porous structure of activated carbon, with the operation range from 1003 to 1043 K. Also the surface area and pore volume of activated carbon could be enhanced by the smaller particle size of petroleum coke, because of the relatively larger particle surface. Through the methane storage analysis, it was observed that higher surface area and pore volume were beneficial to higher adsorption capacity, while the lower methane delivery was attributed to more developed porosity, implying that desorption capacity was also closely related to the porous morphology.