According to research of the Intergovernmental Panel on Climate Change（IPCC），increasing the use of clean energy could effectively reduce the greenhouse gas emission on the Earth，and thus slow down the global warming. Advancing the development of clean energy，as one of the most important measures of retarding the earth warming，more and more appears on the agenda of combating the climate change around the global. Paris Climate Conference in 2015 and the IPCC’s fifth Climate Change Report both put forward the new aims and arrangements for global greenhouse gas reduction. Through the efforts of international community，the ratio of clean energy in the global primary energy supply has increased to a certain extent since the 1970s. On the background of combating climate change and quickening fossil fuel replacement，global clean energy technology R&D and investments both maintain increased in 2014 and 2015，however，the growing rate of both decreased as the result of international oil price slump，week global economic recovery and the European debt crisis.