The utility model relates to the technical field of environmental protection equipment, and particularly relates to a reaction furnace for producing active carbon. A carbonization-activation two-way reaction furnace for producing active carbon through biomass comprises a reaction chamber, a gas delivery pipe I, a gas delivery pipe II, a gas delivery pipe group, support frames and screen meshes, wherein the upper surface and lower surface of the reaction chamber are provided with the support frames, the upper surfaces of the support frames are provided with the screen meshes, and the screen meshes are provided with meshes; one end of the gas delivery pipe I is arranged at the upper side of the reaction chamber, and one end of the gas delivery pipe II is arranged at the lower side of the reaction chamber; purification chambers are respectively arranged at both sides of the reaction chamber. According to the carbonization-activation two-way reaction furnace, the two-way reaction on the biomass is realized by adopting the gas delivery pipes respectively arranged at the upper side and lower side of the reaction furnace; after primary reaction is finished, reaction gas reversely reacts again, so that the reaction efficiency is increased; the reaction and purification inside the reaction furnace are completed together through the purification chambers arranged at both ends of the reaction chamber, and the reaction gas can be directly used without being processed again after being delivered out of the reaction furnace, so that the subsequent process steps of recycling the reaction gas are simplified.