Abstract: The development of new high-performance gas sensors has become particularly urgent with the growth of global energy demand and the aggravation of environmental problems. Biomass char materials are obtained from biomass raw materials through pre-carbonization and activation treatment, which have unique pore structure, large specific surface area, abundant surface active functional groups and active sites, and have great potential for application in the field of gas sensing and detection. In this paper, biomass is classified according to the main sources of biomass char (plant-based, animal-based, and microbial-based) as well as four common preparation methods of biomass char materials (hydrothermal carbonization, activation, templating, and microwave pyrolysis). The paper focuses on the recent research progress of biomass char materials in semiconductor-based gas sensors and non-metallic oxide dominated gas sensors, including their applications as gas-sensitive materials for the detection of various types of gases. Finally, the current problems that need to be solved for biomass charcoal material-based gas sensors are analyzed, and ideas for research and development are proposed to broaden the practical applications of such sensors.