The work aims to prepare the chitosan-gelatin-phenyllactic acid (G-C-NanoPLA) antibacterial composite film with phenyllactic acid nanoparticles (PLANanoPs) as bacteriostatic agents, so as to provide a theoretical basis for the application of phenyllactic acid biopreservatives and the research on new active packaging materials. The PLANanoPs were prepared by ion gel method and added to the chitosan-gelatin matrix to prepare G-C-NanoPLA antibacterial composite films for the preservation of sturgeon fillet. The changes in the total number of colonies, total volatile base nitrogen (TVB-N), pH value, thiobarbituric acid (TBA) value and sensory score of sturgeon during its storage were subsequently determined. The G-C-NanoPLA composite films with mass concentration of 0.1 mg/mL PLANanoPs significantly inhibited the decrease of sensory score and the increase of the total number of colonies, TVB-N, TBA and pH value (P<0.05), and extended the shelf life of sturgeon for 4 days. In conclusion, the G-C-NanoPLA composite film can improve the storage quality and extend the shelf life of sturgeon, which is a very promising active packaging material for seafood.