To achieve high energy-efficiency and to tailor product distribution, pyrolysis followed by CO2 gasification (with the CO2 conversion up to 85%-98%) was proposed for preparation of pine sawdust derived carbons. Effects of the gasification conditions were investigated on properties of the as-prepared carbons. Hierarchically porous carbons can be obtained with some heteroatoms (O and Cl) and thus showing a good capacitive performance (with the capacitance up to 225 F/g at 1A/g).