Abstract: The effect of changes of temperature, time and particle size of charcoal on the adsorptive power and yield of activated carbon obtained through the activation of hardwood charcoal by steam has been studied.The result showed that the optimum condition was activation under the temperature of 900℃ for 4 hours with the particle size of charcoal ranging from 10 to 15 mm. The powder activated carbon produced had methylene blue decoloration 13.5 ml, the yield being 30.3%.