采用双环电化学动电位再活化（DL—EPR）法和动电位电化学阻抗（DEIS）研究了敏化态铁素体不锈钢00Crl2Ti在0．1mol／L H2SO4＋0．0001mol／LKSCN溶液中正反向扫描过程中的电化学行为，并用等效电路图对阻抗数据进行拟合。结果表明：DEIS的变化与DL—EPR曲线上的区域相对应，都呈现出活化区、活化一钝化过渡区、钝化区和再活化区。正向扫描过程中电位0．2V左右开始出现容抗弧变小，且低频区实部减小出现负阻抗，这主要是由于形成的钝化膜还不完整，有局部新鲜表面存在；而反向扫描过程中在0．2V左右阻抗急剧降低，而后逐渐升高，在这个过程中低频一直存在着负阻抗，这主要是由于晶界贫铬钝化膜不稳定，发生局部溶解和修复。发生晶间腐蚀后，低频又出现了负阻抗。由于腐蚀的中间产物吸附在电极表面，低频区出现感抗弧，生成的中间产物的扩散过程为控制步骤；而且DEIS中活化区和再活化区由Rct的最小值的倒数的比值得到的敏化度（DOS）和DL—EPR曲线得到的敏化度存在着一致性。“,”In this paper, double-loop electrochemical potentiokinetic reactivation （DL-EPR） and dynamic electrochemical impedance spectroscopy （DEIS） by forward and reverse potential scan have been used to investigate sensitized ferritic stainless steel 00Crl2Ti exposed to 0.1 mol/L H2SO4＋0.0001 mol/L KSCN solution and fitted with proper equivalent circuits. The results indicated that the region distribution of DEIS is in accordance with that of DL-EPR, including activation region, transition region, passivation region and reac- tivation region. In the passivation region, the capacity loop shrunk at about 0.2 V, and the real part of EIS curve at the low frequency decreased even became negative. The main reason is that the passive film is not complete and a part of fresh surface is exposed to the solution. In the reactivation region, before occurrence of intergranular corrosion, at about 0.2 V, the capacity loop decreased dramatically, and then gradually increased. At the low frequency the EIS displays a capacitive loop with negative resistance, this implies that the passive film suffers rupture and repair due to depletion of Cr at the grain boundary. An inductive loop which is ascribed to the adsorption of intermediate product on the electrode surface indicates that the diffusion process of the intermediate product predominated the corrosion reaction. The degree of sensitivity （DOS） expressed by the ratio of the reciprocal of the minimum Rct in the reactivation region to activation region on DEIS is the same as the DOS from DL-EPR