The passivation behavior of rebar with mill scale and stains, as well as the polished one under anodic polarization in strong alkali environments with and without chloride was investigated. The results show that the polished rebar and the one with mill scale could be passivated under applied anodic current of 50μA/cm2 when pH=125131 without chloride, but only the latter could remain in the passive state when [Cl-]/[OH-]≈1, and both become active when [Cl-]/[OH-]≈5. The rusted rebar stays in active corrosion state despite of existence of chloride, and the applied 50μA/cm2 anodic current is not enough to make it passive.