Activated carbon was widely used in industrial application such as purification of gas and water, catalyst, or catalyst support and separation process etc., owing to its highly adsorption capacity. In this paper, activated carbon was produced from water-melon seed, which is an agricultural by product, by chemical activation with ZnCl₂ NaOH and KOH. Preparation process involve the roasting of raw material and carbonization of roasted material followed by chemical activation. N₂BET specific surface areas of activated water-melon char prepared by chemical activation were measured as 128-978 m²/g with 100-300 wt% chemical ratio of ZnCl₂, NaOH and KOH, respectively. Removal of phenol in solution by activated carbon was carried out and structure change of pore surface was observed by SEM.