Surface water temperature is a key factor influencing the lake aquatic ecosystem. Studying its responses and mechanisms to climate change is an important issue for assessing the sustainability of the lake ecological environment. This paper focuses on the issue of long-term trend of water temperature. Based on the observed hydrological and meteorological data, the evolution characteristics of the lake surface water temperature driven by meteorological conditions were examined by means of the Air2water data-driven model to reconstruct the long-term, time-series water temperature in Lake Dongting, which provides a theoretical basis for the monitoring of lake ecological environment, water security and comprehensive management. The main conclusions are: (1) Although the Air2water data-driven model describes the main heat exchange processes of a lake in a simplified form of an ordinary differential equation, it can well reproduce the actual trend of water temperature. The long-term, time-series observed air temperature can be used to reconstruct the daily averaged water temperature time series in Lake Dongting from 1973 to 2020 with high reliability. (2) From 1973 to 2020, the water temperature within a year in Lake Dongting had apparent warming and cooling periods, where the cooling rates were faster than the warming rates. Driven by the global climate warming, the annual mean water temperature showed consistent increasing trends, and the increasing rates were much more significant after the mutation in 1996, in which the increasing rates of annual mean water temperature at the Chenglingji Station and the Nanju Station were 0.20 and 0.16℃/10 a, respectively. The abrupt warming of Lake Dongting in 1996 was mainly driven by the significant warming process during the cold season. (3) The coupling relationships between water temperature and air temperature have been established using the general unit hydrograph theory, where the rising rates of water temperature with air temperature increased to a maximum value and then gradually slowed down. After the mutation of water temperature in 1996, the rates of water temperature variation with air temperature slightly decreased, indicating that the sensitivity of water temperature to air temperature decreased and the coupling relationships between water temperature and air temperature were weakened.