As two main big economy and carbon dioxide emitter, the cooperation between China and EU are essential to preventing global warming. Hard works have been made between China and EU in promoting the cooperation in the renewable energy field, while there are some conflicts between them. This research tries to illustrate the main institutional and economic support for renewable energy companies both in China and EU member states, the development history and status of the cooperation and conflict between them. Using economic theory such as public goods theory and comparative advantage theory, this research analyzes why the cooperation between China and EU are essential considering the preventing global warming. Based on a case study of solar trade war, the factors behind the conflict in the renewable energy field could be explained. Finally, this research puts forward some policy suggestions about in what specific field should China and EU strengthen their cooperation, what adjustments should be made for the industrial policies in order to avoid or alleviate the conflicts.