Gelatin-based composite films have been widely used in food packaging due to their excellent mechanical properties, barrier properties, antioxidant and antimicrobial activities. This paper reviews the preparation methods and research progress of gelatin-based composite films in the field of food packaging. Firstly, the properties and advantages of gelatin are summarized. Then the preparation methods of gelatin-based composite films are described in detail, including solution casting, melt extrusion, film coating and electrostatic spinning. Then the current research status of plasticizers for gelatin-based films and gelatin-based composite films is analyzed, covering the composite systems of gelatin with glycoconjugates, phenolic compounds, proteins and nanomaterials. In terms of applications, the focus is on the use of gelatin-based composite films in fruit and vegetable preservation, meat preservation and other food products. Finally, a brief outlook on the development of gelatin-based composite films in the field of food packaging is given.