To fill the Gaps of Greenhouse Gas (GHG) inventory for wetland in “2006 IPCC Guidelines for National Greenhouse Gas Inventories” (“IPCC 2006”), the “2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas (GHG) Inventories: Wetlands” (“Wetlands Supplement”) was published to public on February 28, 2014.The “Wetland Supplement” was reviewed from the aspects of the background, the division of wetland types and the methodology for GHG inventory. The GHG methodology was investigated from GHG emission source, GHG account methods and GHG emission factors. Especially, the updates and improvements for the “IPCC 2006” were emphatically discussesd. In general, the “Wetland Supplement” provided the new estimation methods of GHG emissions and removals from coastal wetlands and constructed wetlands for wastewater treatment by human activities, and also updated some key emission factors for various types of wetlands. Considering the present situation in China, the problems demanding prompt solution and the future research trend was pointed out for wetland research area. In the further, this study could provide the scientific basis for wetland GHG inventory in China.