Wetland represents one of the most important land use types, and plays an essential role in the terrestrial carbon cycle. Wetlands are treated as part of "Agriculture, Forestry and Other Land Use (AFOLU)" in national greenhouse gas (GHG) inventory reports submitted by parties to the United Nations Framework Convention on Climate Change (UNFCCC). The GHG budget in wetlands has received much attention from both researchers and policy makers due to the high uncertainties. The Intergovernmental Panel on Climate Change (IPCC) has issued a series of methodological documents since 2006, such as "2006 IPCC Guidelines for National Greenhouse Gas Inventories", "2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories:Wetlands", and "2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories", all of which served as guidelines for national GHG inventories. Despite progresses on GHG inventory methods, the definition and classification of wetlands in IPCC guidelines are inconsistent with those in the Chinese land use classifications. Moreover, the default parameters in IPCC GHG inventory guidelines have largely not been validated against GHG data from the Chinese wetland studies. Therefore, it is imperative to establish a GHG inventory methodology and a parameter set under the IPCC framework and suitable for Chinese wetlands. This paper aims to review the state-of-the-art of GHG inventory in Chinese wetlands. Specifically, this review is intended to (1) compare the methodology of wetland GHG inventory among the three IPCC GHG inventory guidelines and summarizes the updates of the two recent guidelines to "2006 IPCC Guidelines for National Greenhouse Gas Inventories" regarding wetland classification, evaluation method, and default parameters; (2) discuss how and why GHG inventory results for the Chinese wetlands differ from GHG budget estimates based on other methods; (3) clarify how much data from Chinese wetland studies have been incorporated into the databases on emission and removal factors in the three IPCC GHG inventory guidelines; (4) summarize the state of the applications of high-level methodologies for wetland GHG inventory in China. Based on above-mentioned comparisons and summaries, this review proposes that wetland GHG inventory should be improved in terms of promoting data transparency, strengthening the assessment of human activities, and developing high-level methodologies. Such improvements are expected to meet current challenges in wetland GHG inventory, such as the unavailability of activity data and emission factors used in wetland GHG inventory, and a lack of a sophisticated evaluation methodology. This review could help enhance China's ability to carry out wetland GHG inventory, and thereby reduce the uncertainties in the contribution of AFOLU to carbon neutrality.