Abstract: Natural killer (NK) cells, as natural immune lymphocytes, mediate an effective immune response towards virus-infected and malignant transformed cells. Due to its specific recognition and killing mechanism, NK cell has gained wide attention in the field of cancer immunotherapy. However, the durability and effectiveness of NK cell monotherapy in vivo face great challenges. To overcome this problem, more and more studies now focus on the development of therapeutic strategies for NK cell adoptive transfer. This paper reviews the basic biology of NK cells, summarizes the characteristics of different sources of therapeutic NK cells and the methods for the generation of clinical-grade NK cells, and outlines the evolving strategies for genetic manipulation and adoptive transfer that target the functional response of NK cells, so as to provide some reference for the development of NK cell immunotherapy products.