Objective To isolate mononuclear cells from peripheral blood and umbilical cord blood, and to amplify NK cells in them through largescale culture in vitro, and to compare the difference in amplification ratio, quantity and proportion between the two sources of NK cells. Methods Peripheral blood and cord blood were collected, NK cells were expanded by the same culture method, and the number of initial cells, total number of cells, multiplication factor were detected, and the ratio of CD-CD56+ cells was detected by flow method.Results The number of monocytes (starting cells) isolated from the same volume of peripheral blood is more than that of umbilical blood, and the difference between the two is statistically significant (P＜0.05). After culture by the same large system method, the total number of cells expanded from cord blood was more than that from peripheral blood, and the difference was statistically significant (P＜0.01). The expansion ratio of NK cells and CD3-CD56+ cells from cord blood were higher than those from peripheral blood, but there was no significant difference between the two (P＞0.05). Conclusion The same largescale cell culture scheme can not only expand and culture NK cells from peripheral blood, but also expand and culture NK cells from cord blood. The total number of NK cells after culture is different, and the main reason for the difference is the different number of initial cells.