Abstract: As a carbon-neutral renewable energy source, biomass gasification technology represents one of the core pathways for its large-scale utilization. Catalytic upgrading of biomass producer gas achieves high-value conversion through targeted component transformation and efficient impurity removal, offering advantages such as a wide operating temperature range, high product purity, and easy integration with renewable energy systems. Based on the composition characteristics of biomass producer gas, the components are separated into H₂, synthesis gas （CO+H₂）, hydrocarbons, CO₂, pollutants. This systematic review summarizes the current research status of catalytic technologies across five pathways for upgrading biomass producer gas: hydrogen purification and production, synthesis gas component conversion, hydrocarbon reforming, CO₂ capture and conversion, and synergistic pollutant removal. Research reveals that all pathways highly depend on the synergistic mechanism among the active phase, support, and additives of catalysts. In hydrogen production pathways, CeO₂/Fe₂O₃−modified Ni-based catalysts significantly enhance coking resistance. For syngas conversion, Fe-based catalysts favoring low-carbon olefins and Co-based catalysts favoring long-chain alkanes are respectively adapted based on differences in n（H₂）/n（CO） ratios. Hydrocarbon reforming focuses on CH₄ and tar conversion, enhancing stability through bimetallic synergy and mesoporous confinement effects. Although CO₂ capture has established three material systems: Ca-based, amine-based, and MOFs-integration of capture and conversion processes remains relatively low. Pollutant removal demonstrates high efficiency in treating single sulfur or nitrogen compounds but lacks effective solutions for synergistic removal of multiple pollutants. Future research may focus on innovative technical approaches such as rational design of multifunctional catalysts and regulation of oxygen vacancy and interfacial effects to address bottlenecks including insufficient processing capacity, low process integration, and poor catalyst stability.