To describe the preparation methods of modified chitosan in recent years specifically and provide much more and more effective theoretical support for improving the solubility of chitosan, and to illustrate the wide application of chitosan in the pharmaceutical industry. Methods:By referring to the domestic and foreign literatures on chitosan, we summarized the research progress of chitosan in recent years. Results:After the chitosan was modified,its solubility was improved and its application fields were also broadened. Conclusion:The study initially summarizes the modification methods and practical applications of chitosan.And it provides references for the full exploitation of the potential value of chitosan and the further research and development of chitosan.