Based on the combined data of observations, RegCM3 model and the power curve of GE 2.5 MW wind turbine, the interannual variability of wind energy potential (WEP) over 1982-2006 in China is analyzed. It is calculated that the WEP of RegCM3 wind, observation-adjusted wind and their mean wind is 25, 2.5 and 11 PWh/a, all more than 20% of China’s expected electricity demand in 2030 (2 PWh/a). Their relative standard deviations of yearly WEP are about 3%, 8% and 5%, and their relative ranges of yearly WEP are 15%, 33% and 23%. Because of the seasonal variation of wind energy and electricity demand, power deficit could occur in summer if relying on wind energy only, resulting in a need of huge backup capacity that reduces the economic benefit and emission benefit.