Abstract: The carbonization resistance and mechanical properties of concrete containing iron tailings sand under carbonization environments were investigated in this paper.Three factors including water-binder ratio,iron tailings sand content and binder content were analyzed and discussed by orthogonal tests.The results indicate that that water-binder ratio and iron tailings sand content are the most important factors affecting carbonization resistance of the concrete.The concrete is easier carbonized with higher iron tailings sand content,while the concrete containing iron tailings sand with water-binder ratio of 0.4 has the best carbonization resistance.The microstructure shows that ettringite（AFt）and C-S-H gel grow and form dense structure during the hydration process,and AFt decomposes into calcite after carbonization resulting in a significant reduction in structural compactness.