The mercury adsorption characteristics of activated carbon was clarified by the activated carbon column test, which is introduced the simulant flue gas containing mercury. The results showed that the mercury equilibrium adsorption quantity of the activated carbon increases as the mercury concentration in the simulant flue gas increases and as the temperature in the column decreases, the amount of mercury desorbed from the activated carbon increases as the amount of adsorbed mercury in the activated carbon increases and as the temperature in the column increases. Moreover, these behaviors are expressed by Langmuir equation.