Based on the satellite remote sensing data of MODIS, water use efficiency(WUE)in Yunnan Province from 2000 to 2014 was calculated. Combined with the observation data of national meteorological stations, the spatiotemporal variations law of WUE and its main driving factors in Yunnan Province were got by adopting trend analysis, EOF analysis and correlation analysis. The results show that WUE shows apparent spatial gradients across Yunnan Province with lower values in the north and south and higher values in the middle. WUE also shows a clear seasonality in most of the areas, but it does not show strong seasonality in these areas with low WUE values. WUE shows differential trends over the past 15 years across the region with increasing trends dominating in the north and decreasing trends dominating in the south. Evapotranspiration is the dominant factor of its change. WUE spatial mode presents a reverse distribution pattern from north to south, increasing in the north and decreasing in the south, and vice versa. The driving factors of WUE are relative humidity, highest temperature and sunshine hours from north to south, and the correlation shows north-south difference.