Deep eutectic solvents (DES)/reduced graphene oxide (rGO) composite materials can remove dibenzothiophene (DBT) from fuel oil by adsorption desulfurization. However, the whole synthesis process is complicated, and the DES/rGO is high-cost and not strong enough, which limits its application in industry. Therefore, a one-step method to produce DES/rGO composite materials is proposed. The performance of desulfurization was studied and the feasibility of industrial application was analyzed. First, the proposed method can improve the single extraction efficiency to 94.8% without a complicated process. Secondly, the DES/rGO can also be reused and recycled. Third, the proposed method overcomes the inconvenient storage and transportation of liquid DES. Finally, the proposed method could effectively reduce the cost of desulphurization in the industry.