The heavy metal pollution caused by industrial wastewater has become a global environmental problem that threatens ecological security and human health. Developing green and efficient heavy metal recovery technologies is currently one of the core research directions in the fields of environment and biology. Functionalized biomass materials have become important candidates for replacing traditional adsorption materials such as ion exchange resins and commercial activated carbon due to their advantages of renewable raw materials, low cost, environmental compatibility, and adjustable adsorption performance. From the perspective of basic research in recent years, this article reviews the system characteristics, functional modification pathways, adsorption performance, mechanisms, calculation and simulation, environmental and cost analyses of functionalized biomass materials for heavy metal adsorption. The focus is on elucidating the structure performance correlation of different biomass materials, the directional regulation effect of modification methods on adsorption sites, and the microscopic essence of multi mechanism synergistic effects. In response to the problems of uneven raw material activity, weak anti-interference of complex systems, and fragmented mechanism research in current research, future research focuses such as genetic engineering targeted modification, multi-functional group collaborative design, and in-situ dynamic characterization are proposed, providing theoretical support for the precise design and application transformation of high-performance functional biomass materials.