Abstract: The microplastics resulted from the discarded traditional non-degradable plastic filmhas brought a serious threat to ecology. With the gradual implementation of restricting plastic order in China, biodegradable substitutes have become the focus of research and development. In this paper, we used industrial waste gelatin as a cheap raw material and tetrakis hydroxymethyl phosphonium chloride (THPC) as a cross-linking agent to fabricate a novel high strength gelatin-based biodegradable film. Due to the existence of covalent cross-linking network and hydrogen bonds among the gelatin chains in the cross-linked gelatin films, the mechanical properties of the cross-linked gelatin films were remarkably improved. The obtained film exhibited ahighest fracture stress of (29.20±3.86) MPa, and a maximum fracture strain of (2.68±0.26) mm/mm.The film can maintain good physical morphology after 48 h of immersion in water, meanwhile, it has good light transmittance (reached a maximum value of 92.3%) and excellent biodegradability. Considering the comprehensive properties of the film, it has good application potential in packaging and agricultural film. It is expected to be used to replace the traditional petroleum-based non-degradable plastic film and eliminate the negative impact of microplastics on the environment from the source.