We used the optical surface measurement technology to collect the pitting surface data of steel plate specimens subjected to laboratory accelerated corrosion, and discussed on trends of pitting characteristics with the increase of corrosion time by establishing 3D contour pictures of surface data of corroded steel with different corrosion time. For the corroded steel plate mainly with local corrosion, calculations showed that the average depth of pitting corrosion was approximately equal to the average depth of corrosion, and the tendency of the average depth of pitting corrosion with time could be described by a new Weibull function. The pitting section loss ratio, which was perpendicular to the force direction of steel plate, showed a normal distribution, and the relationship between the model parameters and the average depth of pitting corrosion was established. The probabilistic yield strength deterioration model relating to the corrosion ratio was discussed.