With the corroded steel strands from prestress concrete beams contaminated by simulated acid rain, the corrosion rate of the steel strands was calculated and the configuration of the pits were surveyed and classified. Then, with 4 samples of 80 cm long steel strand intercepted at the distribution central areas of the pits, the density, length, width and depth of the pits were obtained to explore the distribution characteristics of size of pits on steel strands corroded by simulated acid rain. The results reveal that the configuration of the pits can be classified as ellipsoid, saddle and pyramid. With the corrosion rates increasing, the pits become denser but its relative increase rates declined. The length is not subject to normal distribution but to lognormal distribution as the depth, and the width approximately is subject to lognormal distribution. The overall distribution characteristics of the pits size are short and narrow and moderate deep, whose length and depth have obvious fractal characteristics, with no obvious fractal characteristics for the width of pits. As the corrosion rates increase, the configuration of all pits trend to approach. The length is found at the relative minor values and the width is found at the relative moderate values, however, the depth is found between the relative minor value and moderate value.