Abstract: In recent years, global climate change is becoming more and more significant. Continuously rising temperatures and CO₂ concentrations will accelerate the carbonation process of concrete, bringing serious challenges to the life-cycle maintenance management of bridges. Based on time-varying reliability method, considering the impacts of climate change and implementation time on maintenance cost, social and environmental impacts of maintenance scheme, this paper establishes a model of bridge performance degradation and maintenance effect under different climate change scenarios. Through quantitative analysis of maintenance cost, social and environmental impact of the maintenance scheme, a climate adaptive optimization method for bridge life-cycle sustainable maintenance strategy is proposed using the NSGA-II multi-objective optimization algorithm. Finally, the above framework is applied to existing bridges, and the optimization results of maintenance strategy are analyzed under different climate change scenarios. The results show that as the climate scenario deteriorates, the increase in reliability indexes caused by the necessary maintenance method varies significant over the implementation time, and the Pareto front obtained from the maintenance strategy optimization continues to spread outward. Under the scenarios of SSP1-1.9, SSP2-4.5 and SSP5-8.5, the number of preventive maintenances of the optimal maintenance strategy in the life-cycle of bridge increases from 4 and 5 to 7, and the implementation time of the first necessary maintenance decreases from 66.8 and 63.1 years to 61.8 years. The proposed optimization framework can obtain reasonable maintenance time and intervals, which provides theoretical support for bridge management departments to formulate climate adaptive sustainable maintenance strategies.