In order to study the spatiotemporal variation of water surface evaporation and predict its trend, the daily data of water surface evaporation, average temperature, relative humidity, average wind speed, and sunshine hours of 43 weather stations in the North-South transition zone of China Meteorological data network from 1980 to 2017 were analyzed by using climate tendency rate, Mann-Kendall（M-K） trend test method, grey correlation analysis method and R/S analysis method. The results show that: from the perspective of time, during the study period, the annual average water surface evaporation in the north-south transition zone showed a significant upward trend, the climate tendency rate was 19.3 mm/10a and a sudden change occurred around 1994, and the water surface evaporation changed from decreasing to increasing; the average interdecadal water surface evaporation also gradually increased; the seasonal upward trend was significant in summer,and not significant in spring,winter and autumn. From a spatial perspective, the climate tendency rate was lower in the middle and northeast of the study area, and higher in other areas. The main reason for the increase in water surface evaporation was the increase in average temperature. In the future, the water surface evaporation in the north-south transition zone will continue to show an upward trend.