The invention discloses a method for carrying out in-vitro efficient amplification on natural killer (NK) cells, and application of the method, aiming at solving the problems that the NK cells amplified by the traditional 
local method are small in amplification times, have 
cytokine dependency and 
cell aging, and the like. The method is characterized by comprising the following steps: 1, separating 
peripheral blood mononuclear cells (PBMCs) from human 
peripheral blood by using the traditional 
Ficoll-Paque 
density gradient centrifugation method; 2, carrying out 100 Grays 
irradiation treatment on 
artificial antigen presenting cells, and then storing by means of 
liquid nitrogen cryopreservation; 3, carrying out co-culture on the PBMCs and the 
artificial antigen presenting cells, subjected to the 
irradiation treatment, in a 
cell culture flask T75 of an RPMI 1640 medium, wherein the 
mass ratio of the PBMCs to the 
artificial antigen presenting cells is equal to 1: 2, and 50IU / mL of 
interleukin 2 is added into the RPMI 1640 medium; replacing the medium with a fresh medium every 2 to 3 days; 4, calculating the number of total cells in the 
cell culture flask T75 every 7 days, adding the same number of 
artificial antigen presenting cells subjected to the 
irradiation treatment into the 
cell culture flask T75 for stimulating again, and continuously culturing for 21 days to obtain the amplified NK cells. Therefore, after the method is adopted, a great deal of high-purity and high-quality NK cells can be obtained.