Abstract: To investigate the characteristics and driving mechanisms of evaporation abrupt changes in the Dianchi Lake Basin under climate change, this study utilizes hydrological and meteorological data from 1960 to 2023.Abrupt change points in the annual evaporation time series were identified using a mutation test method, and the spatiotemporal correlations between evaporation and meteorological elements before and after the abrupt change were quantitatively analyzed using the Pearson correlation method and cross wavelet transform.The results indicate that: ① Annual evaporation in the Dianchi Lake Basin showed a significant decreasing trend with distinct stage characteristics, and an abrupt change occurred in 1989;② Before the abrupt change, changes in evaporation were mainly driven by the physical balance between relative humidity and sunshine duration, with weaker influences from precipitation and temperature.After the abrupt change, temperature rise became the core driving force, coupled with the persistent effects of relative humidity and sunshine duration; ③ Before the abrupt change, there was a 1~5 year resonance cycle between evaporation, precipitation, and average wind speed, which disappeared after the abrupt change.Following the abrupt change, the correlation between evaporation and mean temperature, relative humidity, and sunshine duration significantly strengthened.The analysis suggests that the abrupt change in evaporation in the Dianchi Lake Basin is essentially the result of the coordinated evolution of multiple factors, with the temperature increase dominating the redistribution of energy in the evaporation process after the abrupt change.These findings can provide a reference for studying regional hydrological cycle mechanisms under climate change.