Abstract: Based on the principles of energy flux,the concept of representative section and preferred method for assessment of wave energy resources of islands potential has been proposed for the first time. The third-generation wave spectrum model SWAN is used to numerically simulate the wave field in the South China Sea over the past 10 years and validated against observations. On this basis,the spatial and temporal distribution characteristics of wave energy resources,such as wave height,period and power density,were characterized. And a new method was used to estimate the wave energy resource reserves in the South China Sea. The results show that the theoretical wave energy reserves of the South China Sea Islands are about 18300 MW when the 50 km offshore contour is used as the wave energy input line,of which about 2600 MW are in the Xisha Islands,2120 MW in the Dongsha Islands,6720 MW in the Zhongsha Islands and 6860 MW in the Nansha Islands.