According to the data coming from56sampling stations,characteristics of temporal and spatial distribution and inter-annual change of the evaporation capacity(observed by evaporation pan of type E-601)in Yunnan Province are analyzed and researched.The values of annual evaporation capacity in the edge of the east and west of Yunnan Province are less than those in the valley of the Jinshajiang River basin and in the central region of Yunnan Province.The evaporation capacity in spring and summer is greater than that in autumn and winter.It shows a tendency of reducing for recent 30years.The possible reasons that cause the evaporation capacity wide decreased in1990s are the lessening of sunshine duration and wind speed.