Aquatic products face severe challenges in packaging due to their perishable nature. Traditional materials are ineffective in suppressing microbial proliferation and lipid oxidation, making it urgent to develop efficient preservation solutions. Chitosan, with its excellent film-forming properties, biocompatibility, and antibacterial activity, when combined with plant extracts rich in broad-spectrum antibacterial and antioxidant components such as polyphenols and terpenoids, offers a new approach to aquatic product preservation. This review focuses on the regulatory mechanism of the on-demand release of active components through the structural design of composite films, aiming to break through the bottlenecks of preservation technology. By analyzing the network structure of chitosan, such as porosity, swelling response, and molecular interactions, and their structure-activity relationships with the sustained-release behavior of plant active components, the mechanisms of enhancing the physical properties, antioxidant capacity, and antibacterial activity of composite films are clarified. Studies have shown that this strategy can significantly delay protein degradation and extend the shelf life of aquatic products. In the future, efforts should be made to develop nano-reinforced carriers, multi-component synergistic systems, and spoilage-indicating smart packaging to promote the large-scale application of this technology in the cold chain logistics of aquatic products.