Abstract: Energy supply security has become one of the key issues that constrain the sustainable development. Energy Supplies diversity is a critical measure to secure the Energy Supply.Calculation and analysis of the change of primary supply diversity of China, using Shannon-Weiner index, have shown that, from 1991 to 2005, the diversity index of primary energy supply in China is changed with the change of the structure of energy supply, the change of the proportion of the energy supply proportion with less proportion plays main role; the increase of the amount of energy import that less with proportion of energy supply, the proportion of energy supply becomes evenness, the diversity index of energy supply increase notably, the structure of energy supply trends to optimizing.