Abstract: Chitosan possesses a lot of advantages, including biodegraubility, biocompatibility, non-toxicity, strong antimicrobial andantioxiutive activities, it has become one of hot research topics for chitosan to be applied in foods as natural preservativeandantimicrobial agents.According to a large number of research results, the relationship between molecular structure of chitosan and its antimicrobial and antioxiutive activities was discussed, application of chitosan on food was mainly reviewed.