Abstract The CO2/CH4 adsorption property on shale from Huadian shale gas reservoir in Jilin province of China was investigated at 40 °C with a wide pressure range (CH4: 0-15 MPa; CO2: 0-5 MPa) using a High Pressure Volumetric Analyzer (HPVAII-200), employing the static volumetric method. As the pressure rises, the excess adsorbed amount of CH4 increases gradually, while with the increasing pressure, the excess adsorbed amount of CO2 increases and then reaches the peak at about 4 MPa, followed by a downward trend. Furthermore, when the pressure is less than 5 MPa, the adsorption capacity of CO2 is obviously higher than that of CH4, and compared with CH4, the shale sample will preferentially adsorb CO2, which is beneficial to the application of CO2 enhanced shale gas recovery (CO2-ESGR).