The continuous increase in carbon emissions and the escalating severity of environmental issues, it has become a global focus of attention to explore feasible solutions. Converting CO₂ into useful fuels or chemicals through photocatalysis and electrocatalysis has garnered significant interest. TiO₂ is highly favored for its stable chemical properties, high catalytic activity, low cost, non?toxicity, and environmental friendliness. This review provides an overview of the reaction mechanisms involved in photocatalytic CO₂ reduction and electrocatalytic CO₂ reduction. It emphasizes the key applications and advantages of TiO₂ in these processes, investigates the influence of different surface modification technologies on the catalytic performance of TiO₂, explores how different morphologies of TiO₂ affect the catalytic activity and selectivity of CO₂ reduction, and discusses strategies for enhancing the catalytic performance of TiO₂?based. The overview not only contributes to the existing body of knowledge through additional experimental and theoretical research on the mechanism of titanium dioxide but also provides a scientific basis for the achievement of sustainable carbon conversion processes.