In the three-span concrete cable-stayed bridge, de-icing salt spraying during winter will cause chloride attack on the concrete components, posing significant risk on the corrosion of the reinforcing bars. In order to study the durability performance of this bridge, a numerical simulation based study is proposed. Since different concrete strength grades are adopted for the bridge girder and pylon, different material parameters are input in the numerical simulation process, which describes the chloride diffusion and binding effects. At the same time, due to the complicated cross sections of the girder and pylon, situations with different corner angles are calculated to take the two-dimensional features of the cross sections into consideration. Based on the numerical chloride ingress calculation, three diffusion states of reinforcement corrosion are determined as the criterions. Locations of the reinforcement bars are indicated in the two-dimensional illustration of the three criterions. The most unfavorable sections are selected for the girder and pylon, the corrosion initiation times of which are calculated on the base of the life-cycle analysis. The results indicate that corresponding maintenance strategies are needed for the most unfavorable pylon section at the completion of the bridge, and for the most unfavorable girder section at 40 years of service.