Abstract: Expansive force will occur around the reinforced steel in concrete due to corrosion, and it increases with corrosion damage and, as a result, it will crack the concrete cover so as to shorten the durability of steel-reinforced concrete structures. Based on the elastic mechanics, a corrosion damage calculation model is therefore developed for the steel tube in rectangular steel-reinforced concrete pipes when concrete is cracking due to corrosive expansion, with a relevant formula given. In addition, the influencing factors on the corrosion damage are analyzed, and the results indicate that the corrosion damage increases with the thickness of concrete cover, inner diameter of steel tube and concrete strength grade, but it decreases with increasing outer diameter of steel tube and expansion rate due to corrosion.