Abstract: Based on the "top-down" method, the wood-based composite hydrogels with both high strength and flexibility were prepared by a simple wood "component-structure" design. Firstly, matrix components in the wood cell wall, such as hemicellulose and lignin were selectively removed from natural wood to obtain the cellulosic wood skeleton. Then, the elastic polymers were introduced into the pore structure of the cellulosic wood skeleton, forming the wood-based composite hydrogels. On this basis, functional components were introduced into the wood structure to construct advanced wood-based functionalized hydrogels, which can pave the way for its further application in the fields of flexible sensing, energy-saving buildings, energy storage devices, tissue engineering, and so on. In this paper, the research progress of wood-based composite hydrogels in terms of preparation principle, key processes, functionalization research status and application areas in recent years have been reviewed, and the paper was expected to provide research ideas for promoting the high-value utilization of wood resources.