To ensure the safety of steel structures, it is important to evaluate the time-dependent corrosion behavior. The purpose of this research is to develop a method of predicting time-dependence of the corrosion surfaces of uncoated weathering steel plates in various corrosive environments. Atmospheric exposure tests were carried out on the uncoated steel plates for 0.5, 1, 2 and 4-years in Okinawa Island, Japan. Spatial statistical analyses were carried out on the corrosion surfaces of the tested specimens. In addition to this, the time-dependence of the corrosion surfaces were simulated by the spatial statistical technique.