Activated carbons with high specific surface area were prepared from phenolic resin by alkali activation with sodium hydroxide. This paper discussed the influence of the preparation conditions, such as activation temperature, alkali ratio and precursor particle size. Furthermore, adsorption ability of iodine was examined on the prepared activated carbon. The specific surface area increased with an increase in activation temperature up to 1073 K (2780 m2·g-1) and decreased at 1173 K because of excess activation. The activated carbon, which was prepared at the activation temperature of 1073 K and the alkali ratio of over than 5.0, had very high specific surface area of more than 2000 m2·g-1. It was confirmed that sodium hydroxide worked effectively as the activating reagent in two temperature ranges, below 773 K and above 873 K. The amount of iodine on the prepared activated carbon was much larger than that on the commercial activated carbon.