The work aims to improve the preservation properties of the composite coatings on salmon fillets, and obtain biological preservation materials with long-term and sustained-release properties. With flaxseed gum (FG) and chitosan (CS) as film-forming materials, eugenol (EG) and laurel essential oil (LEO) as preservatives, layer-by-layer FG/CS+EG/FG+LEO composite coating was prepared by casting method. The preservation properties of the composite coatings were evaluated with salmon fillets as objects. FG/CS+EG/FG+LEO composite coating can significantly restrain the growth of microorganisms in salmon meat, improve the water holding capacity of fish meat, and delay fat oxidation, protein decomposition and changes in color difference. The combination of EG and LEO has a certain synergistic effect. At the same time, the action time of biological preservative is effectively prolonged by the slow-release system of multilayer coating, which make the preservation effect of EG and LEO better. Among them, the preservation properties of the FG/CS+EG/FG+LEO composite coating are the optimal, and the shelf life of fresh salmon fillets can be extended from 7 d to 13 d.