Coarse woody debris (CWD) is one of the important components of forest ecosystem, which provides habitat for many species. It is an important consideration for forest and woodland restoration. It includes dead standing tree, fallen wood, large branches and tree stumps and other parts. In the forest ecosystem, CWD represents a large amount of orga nic matter, which contributes to the carbon and nitrogen cycling of the forest ecosystem. Globally, forests absorb about 30 % of the world's man-made emissions of CO2 each year, making them an important carbon sink. As an important ecological unit in forest ecosystem, it plays an important role in productivity, nutrient cycling, carbon sequestration, community renewal and biodiversity. It is suggested that the retention of large amounts of CWD in forest ecosystem can improve the intensity of forest carbon sink. Under the background of global climate change, the world's forests are facing the threat of large-scale unnatural death, and a large amount of CWD is formed in the forests. It is found that natural environmental factors (fire and snowstorm, etc.) are the main causes of CWD, and different forest types and different disturbance environments will show different characteristics of CWD. Increasing the research on CWD is of great significance to global sustainable development and management. This review focuses on the research progress of CWD in forest ecosystems from the aspects of the research situation and hot spots, the formation, source, classification basis and characteristics (reserves and decomposition) of CWD at home and abroad. The classification of CWD with the international unified CWD classification standard is conducive to the comparison of research results, can incorporate the research contents into the unified category of data integration, and improve the world CWD database.