Abstract: Biochar, derived from agricultural waste through pyrolysis and hydrothermal carbonization, has gained significant attention as a sustainable material for food systems. This review systematically examined the effects of different preparation methods on the physicochemical properties of biochar, including its porous structure, specific surface area, and surface functional groups, and explored its multifunctional applications in food production, processing, storage, and packaging. Studies have shown that different preparation processes and modification methods (such as acid, alkali and composite modifications) can significantly regulate the pore structure, specific surface area and surface functional group composition of biochar, thereby affecting its adsorption, antibacterial and catalytic functional characteristics. In food crop cultivation, biochar can enhance soil quality and reduce heavy metal contamination. Additionally, it exhibited strong adsorption and decolonization capabilities in food processing and extended the shelf life of perishable foods by inhibiting microbial growth and oxidation. In food packaging, biochar-based materials demonstrated antibacterial and antioxidant properties and enable intelligent monitoring of food quality. However, challenges remain regarding the precise modulation of functional properties across different biochar sources, the long-term safety assessment of biochar as a food-contact material, and the scalability of production while ensuring consistency and cost-effectiveness. Future research should focus on establishing a comprehensive material-property database, developing novel biochar-based intelligent packaging systems, and constructing a new evaluation framework encompassing standardized production and environmental benefits, to promote the standardized application and sustainable development of biochar in the food industry.