Abstract: Biomass gasification is an important approach for producing low-carbon fuel gas. In order to achieve the lightening of tar components and the directed and efficient generation of fuel gas components such as H₂, CO, and CH₄ during this process, this study systematically reviews the reaction patterns of biomass pyrolysis, volatile reforming, and char gasification under the action of gasifying agents including H₂O, CO₂, and H₂. It explores the influence mechanisms of reaction conditions (temperature, pressure, catalysts, and reactors) on biomass gasification with different gasifying agents and proposes strategies for regulating the generation of fuel gas products. Based on the aforementioned explorations, this study analyzes the fuel gas production capacity, gasification efficiency, and carbon emission processes in biomass gasification. It also looks ahead to the pressing issues that need to be addressed for the further application of biomass gasification technology for fuel gas production and provides corresponding countermeasures. The results reveal that increasing the reaction temperature can promote biomass conversion, tar cracking, and the generation of H₂ and CO. However, excessively high temperatures can cause catalyst particles to grow and deactivate, limit the equilibrium of the methanation reaction, and inhibit CH₄ production. Raising the reaction pressure can, from a kinetic perspective, increase the concentration of the gasifying agent, prolong the residence time of volatiles, and enhance the reaction rates of biomass and its pyrolysis volatiles. From a thermodynamic perspective, high pressure facilitates the methanation reactions of biomass volatiles and char, promoting CH₄ generation, while being unfavorable for reactions such as volatile reforming, carbon dioxide gasification of char, and steam gasification, thereby reducing the yields of CO and H₂. Catalysts can promote tar cracking and increase the production of fuel gas. However, in existing studies, catalysts are typically in a state of particle separation from biomass, making it difficult to enhance biomass conversion rates. Loading catalysts directly onto biomass to catalyze the pyrolysis and gasification of its native chemical structure, thereby achieving high biomass conversion rates and fuel gas yields within short particle residence times, represents an effective approach. A fluidized bed might be a relatively good choice for biomass catalytic gasification. It operates at moderate reaction temperatures, offers rapid transfer rates, and allows supported catalysts to serve as fluidization carriers that come into good contact with biomass. This enables more efficient catalytic conversion of biomass into high-heating-value fuel gas. Under gasifying agent of H₂O, CO₂, and H₂, approximately 1.01 m³ of H₂, 0.67 m³ of CO, and 0.44 m³ of CH₄ can be directionally produced per kilogram of biomass gasified, respectively. Moreover, the process of biomass gasification for fuel gas production exhibits carbon sink characteristics. Biomass steam gasification coupled with hydrogenation gasification and CO₂ methanation can serve as a novel approach for producing "green methane". Currently, the primary challenges confronting biomass gasification technology encompass achieving efficient lightening of tar components, effectively mitigating catalyst deactivation due to carbon deposition, and maximizing biomass gasification within short particle residence times. To address these challenges, employing an integrated experimental-simulation approach to explore optimal kinetic-thermodynamic coupling conditions for biomass gasification, developing low-cost, highly active composite catalysts, and innovating novel direct catalytic conversion technologies for biomass (such as the newly proposed Fe-catalyzed direct hydrogenation gasification of biomass in this study, which achieves a 91.4% biomass conversion rate and a 43.0% CH₄ yield, along with the co-production of light liquid aromatics, within a particle residence time as short as 30 minutes) are of significant importance for the future development of biomass gasification technology. This work advances the fundamental scientific understanding of the complex chemical reaction networks involved in biomass gasification for fuel gas production. Simultaneously, it provides robust theoretical guidance and valuable foundational data references critical for the optimization, control, and practical implementation of this technology.