A copper-modified activated coke (AC-Cu) was prepared through a developed one-step carbonization-activation blending (OCAB) method in which activation (900 degrees C) occurred just behind carbonization (600 degrees C) without cooling and was used in flue-gas desulfurization. Compared with the two-step carbonization-activation blending (TCAB) method, the OCAB method was simplified, and the AC-Cu sulfur capacity improved from 137.0 mg/g (TCAB) to 219.2 mg/g (OCAB). This result can be ascribed to the improvement in the specific surface area and micropore volume of AC-Cu, as well as the increased concentration of C=O and O=C-OH on the surface, since C=O can provide an electron-rich surface for electron transfer and since O=C-OH can form hydrogen bonds with water to facilitate SO2 removal. Remarkably, the specific surface area and surface concentration of C=O and O=C-OH on AC-Cu (OCAB) were all higher than those of Cu/AC (TCAB). All these findings indicated the potential of AC-Cu as a promising efficient material for industrial desulfurization.