Upon performing electrochemical measurements, XPS and TEM characterizations, the influence of sulfide on the passive behavior of Super 13Cr martensitic stainless steel was deciphered. Mechanism interpretation is performed by optimizing the Point Defect Model based upon the impedance data. It is revealed that the passive film display n-type semiconductivity, and the donor density dropped with increasing concentration of sulfide ion. Sulfide ion can induce a current peak at - 250 mV(SCE) (E-peak). The addition of Na2S generates a continuous outer layer which is comprised of Cr(OH)(3), FeS2 and FeS at potential lower than E-peak, and Cr(OH)(3) at potential higher than Epeak. This result leads to the thinner barrier layer and lower charge transfer resistance, implying a weaker protection of the substrate by the passive film.