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采用醋酸溶液改性的石灰石作为CO2高温吸收剂，借助于N2吸附法研究了改性石灰石在循环煅烧／碳酸化反应过程中CaO分形维数的变化规律。结果表明：石灰石经醋酸改性后，其煅烧产物CaO的分形维数得到提高。随循环次数增加，来自天然石灰石CaO的分形维数迅速减小，而来自改性石灰石CaO的分形维数随循环次数增加而下降缓慢，且在相同循环次数时改性石灰石CaO的分形维数均高于天然石灰石CaO。研究发现来自改性和天然石灰石的CaO分形维数与其CO2捕集性能之间，分形维数与比表面积之间都存在着明显的内在联系。改性钙基吸收剂具有更高循环捕集CO2性能的实质是其煅烧产物CaO在循环煅烧／碳酸化过程中保持了较大的分形维数。“,”The limestone modified by acetic acid solution was used to as a CO2 sorbent at high temperature. The change regularity of fractal dimension of CaO derived from modified limestone during cyclic calcination/carbonation reactions was investigated by N2 absorption method. The results show that the fractal dimension of CaO derived from limestone increases after the modification by acetic acid. The fractal dimension of CaO derived from the natural limestone exhibits a rapid decrease with the number of cycles, while that of the CaO derived from the modified sorbent shows a slow reduction at the same reaction conditions. CaO obtained from the modified limestone dispjays higher fractal dimension than that from the natural sorbent after the same number of cycles. The obvious interrelation between the fractal dimensions of CaO derived from the modified and natural limestones and their CO2 capture capacity was found. Also, the relationship between fractal dimension and specific surface area was discovered. The modified calcium-based sorbent possesses greater cyclic CO2 capture capacity, in essence, because CaO derived from the modified sorbent remains higher fractal dimension during cyclic calcination/carbonation reactions.