Abstract: To explore the potential of essential oil (EO) in preserving marine fish, cinnamon essential oil (CEO) was loaded onto attapulgite clay (ATP) to form a stable composite. The characteristics, antimicrobial activity, and efficacy of this composite in application in fish preservation were evaluated. The results showed that the EO was bound to the ATP surface through intermolecular interaction forces. The results of the in vitro testing demonstrated that the ATP-CEO composite exhibited a strong and sustained antibacterial activity. Assessed by total volatile basic nitrogen analysis, the ATP-CEO preservation film extended the shelf life of sea bass from 4 to 10 days and that of salmon from 6 to 14 days. Meanwhile, the quality indexes, such as texture and water-holding capacity of the fish, were significantly better (p<0.05) than those of the control group. Overall, the results indicated that the ATP-CEO composite has the potential to be a sustainable natural preservation method for the storage and preservation of sea bass and salmon fillets.