As an important part of ecological environment and water resources assessment, timely and accurate analysis of spatio-temporal characteristics of regional evapotranspiration and its relationship with climate factors, is of great significance to the regional weather, hydrology, water conservancy and agricultural fields. In this article, we analyzed the inter-annual variation and annual variation of surface evapotranspiration in the Dongting Lake Basin during 2000-2014 based on the time series MOD16 dataset. And the correlation between evapotranspiration and climate factors was discussed by using regression model based on the annual precipitation and temperature data of study area. The results show that: 1) Based on the measured evapotranspiration of Taoyuan station, we validated the MOD16 dataset. The correlation coefficient between the measured evapotranspiration and surface evapotranspiration from MOD16 was 0.88, which met the needs of accuracy of the study on the spatial and temporal distribution of evapotranspiration in Dongting Lake Basin; 2) The annual evapotranspiration value of Dongting Lake Basin has a strong spatial differentiation pattern, showing a trend of being low in the northeast area, and high in western and southern areas of the study area. During the study period, the average annual evapotranspiration in Dongting Lake Basin was 636.83 mm/a, which showed a downward trend with irregular fluctuations. The highest evapotranspiration value appeared in 2001, which was 669.19 mm/a, and the lowest evapotranspiration value was 613.62mm/a, which appeared in 2011. The change rate of annual surface evapotranspiration (theta) was -2.98%, which indicated that the evapotranspiration value showed a downward trend of Dongting Lake Basin. The spatial distribution of evapotranspiration was related to land cover types, which had effect on the evapotranspiration distribution in the Dongting Lake Basin, and the order of evapotranspiration intensity of different land cover types was forest > grassland > bare land > cultivated land > town. 3) The seasonal variation of evapotranspiration value was obvious, and the evapotranspiration in summer was the highest. The order of evapotranspiration value of different seasons was Summer > Spring > Autumn > Winter. 4) Furthermore, the annual variation of evapotranspiration in Dongting Lake Basin showed a unimodal pattern that increased first and then decreased. The high value area of monthly evapotranspiration was mainly concentrated between May and September, the minimum value appeared in December, and the peak value occurred in July. 5) The correlation coefficients between surface evapotranspiration and precipitation and temperature were 0.67 and 0.41, respectively. Most of the regional precipitation and temperature have a positive correlation with surface evapotranspiration in Dongting Lake Basin. Comparatively, the correlation between surface evapotranspiration and precipitation was stronger than that between surface evapotranspiration and temperature. The humid climatic condition is beneficial to the growth and development of vegetation. With the increase of vegetation coverage, the value of surface evapotranspiration also increases. However, a higher temperature and less precipitation, being not conducive to the growth of vegetation, results in low surface evapotranspiration. According to the above analysis of this article, it can be further explained that the coupling effect of temperature and precipitation is an important factor affecting the surface evapotranspiration in Dongting Lake Basin.