Abstract: Climate warming will change the evolution of thermal regime of reservoirs, and further affect the water environment and aquatic ecological process. In view of obtaining the evolution trend and range of the thermal regime of the water supply reservoirs with steady stratification of water temperature under the background of current climate warming，in this paper，taking the Chongqing Liyutang Reservoir as a research object, a 2D reservoir water temperature model with average width was constructed to simulate the water temperature change process of Liyutang Reservoir under four future air temperature change scenarios, and to study the influence of climate warming on reservoir thermal regime and water quality. The results showed that the temperature of surface water, bottom water and discharged water all responded to the change of air temperature, and the significance of the warming trend and the rate of warming increased with the increasing of greenhouse gas emission concentration. With the increasing of greenhouse gas emission concentration, the starting time of reservoir water temperature stratification had been advanced, and the ending time of stratification had been significantly delayed, while the reservoir thermal stability was significantly enhanced, which made the water body's vertical mixing capacity weakened. Climate warming caused the overall increase of water temperature and the extension of stratification time of the reservoir, which would increase the risk of algae outbreaks and the difficulty of controlling the algae in the reservoir, which should be paid more attention to in the reservoir management.