Abstract: Steel corrosion is one of the important influence factors for durability of reinforced concrete structures. For different engineering structures, different criteria on durability are established, in which the initial rustiness time of steel and the initial crack time of concrete are two key factors. In this paper, steel rustiness and concrete cracking were selected as indicators of structural durability, and an assumptive model of steel rustiness development was advanced. Meanwhile, the model parameters were calibrated. Damage mechanics theories were applied and the damage of concrete structures due to steel rustiness and expanding was simulated numerically. The endurance life of structures can be evaluated and predicted based on the foregoing analysis accompanying with the corrosion analysis of the protective layer.