The　surface　activity　of　carbon　black　(CB)　is　an　important　factor　affecting　the　reinforcement　of　rubber.　The　quantitative　determination　of　the　surface　activity　(surface　free　energy)　of　CB　is　of　great　significance.　A　simplified　formula　is　obtained　to　determine　the　free　energy　of　CB　surface　through　theoretical　analysis　and　mathematical　derivation.　The　surface　free　energy　for　four　kinds　of　industrial　CBs　were　measured　by　inverse　gas　chromatography,　and　the　influential　factors　were　studied.　The　results　showed　that　the　aging　time　of　the　chromatographic　column　plays　an　important　role　in　accurate　measurement　of　the　surface　free　energy　of　CB,　in　comparison　with　the　influences　from　the　inlet　pressure　and　carrier　gas　flow　rate　of　the　chromatographic　column　filled　with　CB.　Several　kinds　of　industrial　CB　were　treated　at　high　temperature,　and　the　surface　free　energy　of　CB　had　a　significant　increase.　With　the　increase　of　surface　free　energy,　the　maximum　torque　was　decreased　significantly,　the　elongation　at　break　tended　to　increase,　the　heat　generation　of　vulcanizates　was　increased,　and　the　wear　resistance　was　decreased.　©　2020　S.　Zhang　et　al.,　published　by　De　Gruyter.