The reinforced concrete structures in offshore atmospheric environment are eroded by chloride ions all the year round, and the seismic performance of the structures deteriorates continuously during the service period. In order to study the change law of seismic damage risk of reinforced concrete curved Bridges in offshore atmospheric environment, based on previous research results, this paper determined the probability distribution types of different environmental parameters and corrosion parameters, and built a probability-based reinforced concrete material deterioration model under chloride ion erosion effect. The finite element model of curved bridge under offshore atmospheric environment is established on OpenSEES platform, and then the time-varying seismic vulnerability of bridge components and system is analyzed respectively. The results show that, under the same intensity of seismic load, with the increase of service time, the exceedance probability of pier under various damage conditions increases, while the probability of support damage decreases slightly. With the increase of fortification intensity, the vulnerability curve of components tends to be flat, and the seismic capacity is constantly improved. In addition, the damage probability of the bridge system is higher than that of the component, so the vulnerability analysis results of the component and the system should be considered comprehensively when the seismic performance evaluation of the bridge structure is carried out.