Enzyme-based biosensors convert molecular recognition events into measurable signals through enzymatic catalysis and can further amplify such signals via catalytic cascades, offering promise for rapid safety testing of aquatic products. However, the susceptibility of free enzymes to inactivation and their limited storage stability constrain practical applications. Metal-organic frameworks (MOFs), with tunable pore structures and interfacial properties, can improve enzyme stability through immobilization and provide versatile strategies for analyte enrichment and signal transduction. This review outlines the structural features of MOFs and major enzyme immobilization methods, including surface adsorption, covalent binding, in situ encapsulation, and pore infiltration. Four sensing mechanisms are summarized: enzymatic conversion of the analyte, analyte-induced enzyme inhibition, restoration of enzyme activity through competitive release, and affinity recognition-mediated indirect enzymatic detection. Particular attention is given to advances in detecting aquaculture drug residues, food additives, foodborne pathogenic bacteria, and freshness markers, with an assessment of sensor performance and applicability in aquatic product samples. Current challenges and future research directions are discussed, focusing on the balance between enzyme activity retention and mass transfer efficiency, analytical reliability in complex aquatic product matrices, and portable sensing applications. This review provides insights into the design of biosensors based on MOF-immobilized enzymes and their application to aquatic product safety monitoring.