In order to realize the new situation of safe, economic, and low-carbon bridge maintenance and ensure the efficient operation of the bridge during the maintenance period, the reliability evaluation model of the deteriorated bridge was obtained based on the reliability theory. According to the carbon emission factor method, the carbon emission calculation model of the bridge maintenance stage was established. An objective function considering bridge reliability, maintenance cost, and carbon emission was constructed. Based on the objective function and bridge reliability constraints, a multi-objective optimization model of bridge maintenance strategy considering carbon emission was formed. By taking a bridge as an engineering example, the optimal maintenance strategies considering different weights were obtained, and the single maintenance behavior and the combined maintenance behavior were compared. The results show that decision-makers can choose bridge maintenance strategies according to different needs. In the case of emphasizing economic benefits, the maintenance cost is the lowest, but the reliability is small. When the environmental impact is emphasized, its carbon emission is the lowest, but its reliability is the lowest. When the overall performance is emphasized, its reliability is the highest, but its carbon emissions and maintenance costs are the highest. With the same weight, its carbon emission, maintenance cost, and reliability are more balanced. The carbon emission of combined maintenance behavior is similar to that of pasted steel plate and external prestressing method, but the maintenance cost of combined maintenance behavior is smaller. The increased section method produces the most carbon emissions, and the pasted FRP has the least carbon emissions, but the total maintenance cost is the highest.