<p>Covalent organic frameworks (COFs) have emerged as promising photocatalysts due to their designable pore structures, high surface areas, and tunable electronic properties. However, their practical applications are often hindered by inherent limitations, such as high exciton binding energy, poor charge carrier mobility, and sluggish interfacial reaction kinetics. Recently, local microenvironment regulation has proven to be an effective strategy to enhance the photocatalytic performance of COFs. This review comprehensively summarizes various regulation approaches, including element doping, polar functional group modulation, pore size and structure engineering, structure regulation, molecular structure fabrication, linkage regulation, post-synthetic ionic functionalization, chemical bond regulation, and layer-stacking strategy. These methods enable precise control over the electronic structure, pore polarity, and active-site microenvironment of COFs, thereby significantly improving the photogenerated charge separation, reactant adsorption, and catalytic conversion efficiency. This review highlights the successful application of these strategies in photocatalytic hydrogen evolution, CO₂ reduction, and H₂O₂ production. It concludes with perspectives on future challenges in green synthesis, multi-scale microenvironment engineering, mechanistic understanding, and device integration for sustainable solar-to-chemical energy conversion.</p>