As one of the most effective methods for low-grade ore separation, flotation has the advantages of obvious sorting effect on fine-grained ores and high separation efficiency. It is crucial to use reasonable and eco-friendly depressants in order to improve the flotation separation effect. As a new type of organic depressant, chitosan is widely used in mineral flotation due to its outstanding physical and chemical properties, environmental protection and easy preparation. Many chitosan derivatives also have excellent depression capabilities. In this work, the research progress of chitosan and its derivatives in flotation experiments of various minerals in recent years is reviewed. Firstly, the main adsorption methods of chitosan and its various novel derivatives as flotation depressants on mineral surfaces are introduced. Then, the depression mechanism and the main factors affecting the depression effect are summarized. Discussion and potential future research directions of chitosan derivatives depressants are also included. Although the research on chitosan and its derivative depressants is becoming more and more mature, the main depression mechanism is still not detailed enough. With the advancement of various detection methods, how to improve the depression effect and further clarify the related groups and main depression mechanisms will be a major focus of future research on chitosan derivatives depressants.