<p>The frequent occurrence of fire disasters has posed a serious threat to the environment, human life and economic systems, thereby driving the development of fire safety strategies. In recent years, significant progress has been achieved in smart fire warning systems, which integrate multifunctional sensing, rapid response capability, and enhanced environmental adaptability. However, most studies have primarily focused on the sensing performance of highly conductive functional fillers, while the roles of other components within these systems have largely been overlooked. With the increasing demand for sustainable, multifunctional, and structurally integrated fire warning materials, biomass and biomass-derived components have been widely incorporated into fire warning sensing systems, often serving as major structural or functional constituents. Their intrinsic renewability, hierarchical architectures, rich surface chemistry, and tunable physicochemical properties provide unique advantages for the construction of multifunctional sensing platforms. This review discusses recent advances in the utilization of biomass and biomass-derived materials in smart fire warning systems, with emphasis on their roles in conductive network construction, thermal and flame-retardant enhancement, mechanical strength and flexibility, as well as sensitivity to fire-related environmental stimuli. Strategies for integrating biomass into fire warning systems, including carbonization, chemical functionalization, composite engineering, and structural design, are also systematically discussed. In addition, the environmental sustainability of these systems is assessed in terms of green fabrication, biodegradability, and recyclability. Finally, current challenges and future opportunities are highlighted, outlining directions for future development.</p>