This paper explored the evolution of global climate governance and its development model，analyzed the main contents and stages of G20’s climate governance，examined the characteristics and institutional advantages of G20’s climate governance，and discussed the integration prospects of G20 climate mechanisms and the United Nations Framework Convention on Climate Change Convention（UNFCCC） mechanisms. It found that although the G20 itself is not a mandatory institution，the parallel development of the UNFCCC mechanisms and other international mechanisms has become the basic model of global climate governance. At the same time，the Paris Agreement is inherently deficient and cannot respond effectively to climate change. The non-UNFCCC mechanisms are expected to continue to play a role in addressing global climate cooperation. G20 has the solid strength and institutional advantages to lead global climate governance，and it is expected that G20 will converge to the UNFCCC system to a certain extent.