Abstract: Achieving carbon emission peak before 2030 and carbon neutrality before 2060 in China (refer as “double carbon”objectives) is a solemn commitment to international community, which has been categorized into ecological civilization construction. Ecosystem carbon sink is an important way to achieving “double carbon” objectives and the certain requirement of high quality development of forest and grassland. The carbon storage and carbon cycle of global forest, grassland and wetland has been evaluated by international agencies. The countries listing in Appendix 1 (developed countries and transitional economies of OECD in Appendix 1 of United Nations Framework Convention on Climate Change) have estimated the carbon emission and carbon sink in their own countries, and compiled the annual GHG lists. Besides, China has also launched five times of GHG lists, which have provided the foundation for dealing with climate change in China. During the process of establishing route maps and time tables of “double carbon” objectives, the authors suggested that not only the temporal and spatial differences between ecological carbon sink and carbon emission from energy and industry activities should be considered, but also the special features of ecological carbon sink and carbon emission. Ecological carbon sink is not the necessary option of carbon emission peak, but it is the necessary option of carbon neutrality. Ecological carbon sink should be consistent with the basic principles of the national “double carbon” objectives, and it also should be the main objectives of ecosystem construction and protection project. Besides, the carbon sink survey and measurement ability should be improved, and the carbon market and financing mechanism should also be perfected.