Abstract: Phenolic resin was in-situ synthesized on the surface of commercial coconut shell activated carbon for the regulation of pore size distribution, using formaldehyde and phenol as the precursors. Then, the samples were carbonized under high temperature. The samples carbonized at 850-900℃ for 1h had methyl blue (MB) adsorption capacity 60mg/g, much lower than the original sample, while they had iodine adsorption capacity above 1 000 mg/g, close to the original sample. This result illustrated that the residual carbon from the polymer was efficiently adopted on the wall of meso- and macropores. It led to the increasing amount of micropores. The existence of residual carbon was further proved by surface area analysis, thermal gravimetric (TG) analysis, elemental analysis and other characterization methods. They coincided with the results of MB and iodine adsorption experiments. Hence, the pore size distribution is able to be efficiently regulated by the adoption and carbonization of phenolic resin.