Abstract: Mesocarbon microbeads (MCMBss) were activated by KOH and K2CO3 and were analyzed by Xray diffraction, nitrogen adsorption and scanning electron microscopy. Results showed that the KOH activated MCMBss had a BET surface area of 2775m2/g. They had an amorphous structure and graphite crystallites were destroyed by activation. The activation mechanism involves a series of chemical reactions and potassium intercalation.