In this study, CuO-based sorbents were prepared to investigate their characteristics of the reduction and sulfurization reactions. CS sorbents were prepared with various contents of CuO and SiO2. CMS sorbents were prepared with 25 wt% SiO2 and various contents of CuO and MoO3. CFS sorbents were composed of 25 wt% SiO2 and various contents of CuO and Fe2O3. All sorbents were prepared using the simple mixing method which was known to be economical and easy to apply. In order to investigate reactivities of the prepared sorbents in the reduction and sulfurization reactions, TGA experiments were performed, and the activation energies of the reactions were calculated based on the Chatterjee-Conrad method. Experimental results showed that the activation energy increased as the contents of SiO2 decreased for the reduction reaction. The activation energy decreased as the contents of SiO2 decreased for the sulfurization reaction. The sorbents without additives gave better performances than the sorbents containing additives in terms of the activation energy for the reduction and the sulfurization reactions. CFS sorbents showed more favorable activation energy than CMS sorbents.