Collagen is the most abundant extracellular matrix protein in mammals and possesses a unique three-dimensional helical structure; gelatin is a mixture of amorphous protein chains obtained by the partial hydrolysis of collagen. Both possess excellent physicochemical properties, including gel-forming ability, biocompatibility, bioactivity, biodegradability and low toxicity, and have become widely used hydrogel matrix materials in the fields of tissue engineering and the food industry. This review discusses diverse modification strategies for collagen- and gelatin-based hydrogels, including chemical covalent modification, physical modification, nanocomposites and enzymatic modification; focusing on the functional requirements of the tissue engineering and food industries, it explores cutting-edge application research on these hydrogels in areas such as mechanical adaptation, angiogenesis, immunomodulation, 3D bioprinting, active substance delivery, food modification and packaging. This review highlights the challenges currently faced in clinical translation and large-scale production, proposes solutions, and outlines future development directions, with the aim of providing guidance for the development and application of novel collagen/gelatin-based hydrogels.