Photocatalytic technology has attracted considerable attention in recent years due to its significant potential in environmental protection and energy conversion. Covalent organic frameworks (COFs), a novel class of porous materials, demonstrate remarkable photocatalytic performance owing to their high surface areas, tunable pore sizes, permanent porosities, and customizable functionalities. This review provides a comprehensive overview of the application of COFs in photocatalysis. In energy-related applications, COFs effectively catalyze hydrogen (H2) and hydrogen peroxide (H2O2) generation, and uranium (U(VI)) extraction from seawater, thereby offering new avenues for sustainable energy generation. In environmental remediation, COFs exploit photocatalytic properties to reduce CO2 emissions and degrade antibiotics in wastewater, thereby contributing to greenhouse gas mitigation and the enhancement of water quality. The review further explores the underlying mechanisms of COFs in photocatalytic H2 and H2O2 generation, U(VI) reduction, CO2 reduction, and antibiotic degradation, emphasizing the synergy between COF structure and photocatalytic performance. Nevertheless, challenges persist concerning the stability, catalytic efficiency, and scalability of COFs. Future research should prioritize optimizing synthesis methods, tuning structural features, and enhancing the stability and performance of COFs to facilitate their practical applications. These advancements are crucial for promoting the widespread adoption of photocatalytic technologies in the energy and environmental sectors.