Woody debris plays a critical role in maintaining species diversity,offering habitats,breeding grounds,and nutritional support to a variety of organisms. This review synthesizes the impact of woody debris on species diversity,drawing on studies spanning the last two decades and encompassing the diversity of animals,microorganisms,and plants within woody debris habitats. Mechanisms through which the individual attributes of woody debris are analysed,including origin,size,decomposition stage,and tree species-affect species diversity. For instance,larger woody debris provides stable microhabitats over extended periods,thereby supporting higher species richness,while specific tree species create unique ecological niches due to their distinct chemical and physical properties. The decomposition process,which occurs in distinct stages,drives dynamic changes in species composition,with each stage fostering specific ecological interactions. Additionally,the origin of woody debris-whether derived from natural events such as storms,fires,and insect outbreaks,or human activities like logging-plays a significant role in determining its quantity,quality,and habitat potential,thereby shaping biodiversity outcomes across different forest types. The review also discusses how changes in the quantity,characteristics,and spatial-temporal continuity of woody debris,resulting from forest management activities,affect biodiversity. Intensive forest management frequently reduces the volume and structural diversity of woody debris,negatively impacting specialized and rare species. In contrast,strategies that promote natural forest dynamics or adopt adaptive management approaches enhance habitat heterogeneity,thereby benefiting a wide array of organisms. Maintaining diverse types and decomposition stages of woody debris is crucial for supporting species across multiple trophic levels,including fungi,invertebrates,birds,and mammals. Furthermore,the spatial connectivity of woody debris is essential for low-dispersal species,underscoring the importance of landscape-scale planning to ensure habitat availability and ecological resilience. Building on existing knowledge,four key future research directions are identified: incorporating woody debris into adaptive forest management strategies,assessing the relationship between woody debris and species diversity under climate change,investigating the effects of extreme disturbance events on wood-dwelling species communities,and exploring the relationship between bark characteristics of woody debris and community structure. This review aims to provide scientific guidance for the management of forest woody debris and offer new perspectives for the conservation of species diversity in forest ecosystems.