As a green and natural packaging material, chitosan is an ideal substitute for plastics and a preferred functional material in food packaging industry. In order to reflect its antimicrobial application value, the antimicrobial mechanism of chitosan was combed firstly before the factors affecting antimicrobial properties were analyzed. It was found that the antibacterial activity of chitosan was not only related to its molecular structure, but also to its relative molecular weight, degree of deacetylation and external environment. In addition, by summarizing the modification method to improve the antibacterial function of chitosan and its application in edibles such as fruits and vegetables and meat, it was shown that modified chitosan has enhanced the antimicrobial properties as well as improved barrier properties and mechanical properties. More importantly, the packaging materials had antibacterial and preservation properties in food packaging. In conclusion, the modified chitosan-based antimicrobial food packaging materials were reviewed, with a view to providing theoretical basis and research ideas for the preparation of green antibacterial food packaging materials, and promoting the development and application of functional food packaging materials as well.