The concept of climate finance was originated from the United Nations Framework Convention on Climate Change(UNFCCC). The climate finance referred in the UNFCCC only includes new and stable funding from the developed countries to support developing countries in their response to climate change. Along with the change of the pattern of the world's economy and trade and the development of the process of climate negotiations,changes and evolution take place in both the concept and the connotation of climate fund,fundamental institution of international climate fund and the efficiency criteria on the actual use of the fund. Based on the comprehensive analysis of the newest legal documents on the climate finance mechanisms,information notifications,document literature,think-tank reports,this paper analyses the key elements in the concept of climate finance,and conducts comparative analyses on the newest tendency of developments of both UNFCCC and Non-UNFCCC financial mechanisms. Based on the analyses above,the paper pointed out that the UNFCCC fails to provide an implementable binding arrangement for developed countries to fulfill their funding commitment. As the boundary between the public fundingand privatecapitals is gradually blurring in the complicated international climate financial system,the principle ofadditionalityandincremental costis being marginalized in the process of funding transfer. At the last part,the paper pointed out that China should insist that there is a clear line between climate finance and ODA,and at the same time,seek to participate with the new multilateral and bilateral financial mechanisms. And the sound development of domestic carbon price signals,the establishment of domestic climate fund as the official financial intermediary both for collecting funds and investment abroad are also important countermeasures for China.