In this research, composites of a well-known metal-organic framework, CuBTC, and activated carbon (AC) are synthesized through solvothermal method and their performance is evaluated from viewpoint of CO2/H2 separation. For this purpose, different amounts of functionalized AC are incorporated in CuBTC structure and a volumetric-chromatographic technique is employed to measure the selectivity of CO2 over H2. XRD patterns, BET surface area, and FESEM images are employed to determine textural properties of as-synthesized samples. It is demonstrated that, while crystalline structure of CuBTC is not affected by incorporation of AC particles, adding proper amounts of functionalized AC to CuBTC matrix can cause higher CO2/H2 separation factor at low pressure and 298 K. Obtained results suggest that adding 0.050 g AC to CuBTC can increase the CO2/H2 selectivity up to around 32 which is double the separation factor of bare CuBTC (i.e. ≈ 15). Enhanced hydrogen separation behavior might be attributed to the presence of carbonyl and nitrile functional groups exhibiting CO2 adsorption affinity on the surface of AC added to the optimum CuBTC structure.