Metal surface corrosion and wear can be improved by micro-arc oxidation. The micro-arc oxidation coatings commonly exhibited porous structure, which is considered to be main reason for failure of corrosion resistance and high temperature oxidation resistance. Arsing of that, in this paper, the corrosion resistant properties of micro-arc oxidated coatings was improved by self-sealing microstructure through an applied electric field. The relationship between the porous structure of the oxidation coatings and corrosion was investgated by microstructure anylisis. Meanwhile, regularity relations of colloid motion-potential-porous structure during sealing process was discussed and the corrosion resistance of the coatings after self-sealing was evaluated by electrochemical corrosion test. The main results showed that the porous structure of the coatings is the channel corrosive medium, and corrosion resistance can be improved by the self-sealing. In addition, corrosion resistance exhibited significant dependence on porosity, composition and morphology of sealings. It is known from this paper, the corrosion resistance can be improved by self-sealing microstructure obtained by applied electric field.