Abstract: Nanotechnology has shown obvious advantages in the field of medical treatment and diagnosis. Through the encapsulation of nano carriers, drugs not only enhance the therapeutic effect and reduce toxic and side effects, but also become intelligent responsive targeted drug systems through the modification on the surface of nano carriers. However, due to the obstacles in relevant basic research, production conditions, cost, clinical trials, and the lack of pharmacokinetic research on various drug loading systems, few nano systems have been used in therapy. In order to solve the above problems, this paper reviewed and analyzed the research progress of nano carriers in drug delivery, including their auxiliary role and characteristics, types and functions, pharmacokinetics, application prospects and challenges.