Abstract Osteomyelitis is a complex infectious disease caused by bacterial infection, which has always been a difficult problem for clinical orthopedic surgeons. Although the traditional methods are effective in treating osteomyelitis, the heavy use of antibiotics and surgical treatment cause serious side effects and lead to bone loss and healing difficulties after surgery. Chitosan (CS), a natural polymer material, is a deacetylated derivative of chitin, which has good biodegradability, antibacterial, and osteogenic properties, and has been widely used in the treatment of osteomyelitis. In this review, the recent research progress in the application of CS based composites such as micro-nano drug delivery carriers, hydrogels, coating materials, and bone tissue engineering scaffolds for the treatment of osteomyelitis is summarized, in order to provide certain experimental and theoretical support for the development of CS based composites.