The invention discloses a production method of high specific surface area active carbon, which includes the steps of: 1) screening of raw material carbon: sieving raw material carbon, and selecting raw material carbon being 6-20 meshes in granularity; 2) pretreatment of the raw material carbon: uniformly mixing potassium hydroxide with the screened raw material carbon, and transferring the mixture into a microwave heating device to perform microwave heating under protection by nitrogen gas to form pretreated carbon; 3) water vapor activation: transferring the pretreated carbon into an activating furnace, feeding nitrogen gas to expel the air in the furnace, and feeding water vapor to activate the pretreated carbon; 4) CO2 activation: after the water vapor activation is finished, feeding CO2 and reducing the amount of the water vapor to perform CO2 activation, and after the activation is finished, continuously feeding nitrogen gas until the temperature is reduced to room temperature to form an activated product; 5) discharge: washing and drying the activated product and discharging the high specific surface area active carbon. The method has simple operation and short activating time, is high in mesoporous ratio, and is low in production cost.