Abstract: This is an essay in the field of environmental engineering. The experiment adopts the impregnation method, and uses FeCl₃ as the modifier to modify the activated carbon to study its desulfurization ability. The effects of modifier concentration, roasting temperature, and reaction temperature on the desulfurization performance of modified activated carbon were experimentally studied. Studies have shown that as the concentration of the modified solution increases, the Fe₂O₃ attached to the surface of the activated carbon increases, the specific surface area and total pore volume of the modified activated carbon decrease, and the average pore size increases; as the roasting temperature increases, the amount of Fe₂O₃ attached to the surface of the activated carbon continues. When the roasting temperature exceeds 300 ℃, the pore structure of the activated carbon surface will be sintered, which will reduce the desulfurization performance of the modified activated carbon; as the reaction temperature increases, the adsorption performance of FeCl₃/AC-0.15 first increases and then decreases. When the concentration of FeCl₃ modified solution is 0.15 mol/L, the calcination temperature is 300 ℃, and the reaction temperature is 60 ℃, the desulfurization efficiency of modified activated carbon is the highest.