Abstract: Chitosan nanoparticles have attracted much attention in biomedical field in recent years because of their easy modification, good biocompatibility, easy degradation and wide sources. Chitosan nanoparticles is a new type of carrier, has significant effect in improving drug stability, achieving drug controlled release and improving drug cell uptake compared with the traditional nano carrier. However, before the clinical application of chitosan nanoparticles, it is necessary to predict and evaluate its potential toxicity and adverse reactions, and clarify the absorption, distribution, excretion, biocompatibility and toxicity of chitosan nanoparticles in vivo, so as to ensure the effectiveness and safety. In this paper, the progress in application of chitosan nanoparticles in drug delivery systems was reviewed, and the research progresses of pharmacokinetics, biocompatibility and toxicity of chitosan nanoparticles were summarized.