Abstract: Objective:To study the changes of CD3⁺、 CD3⁺CD4⁺、 CD3⁺CD8⁺、 CD3^-CD16+56⁺（NK cell）、 CD3⁺CD16+56⁺（NKT cell）cells after amplification of 23 malignant tumor patients from peripheral blood in vitro,observing the biologic security of the lymphocyte after amplification in vitro and transfusion to the patients.Methods: Inducing and amplifying the lymphocyte and mononuclear cells from peripheral blood of malignant tumor patients,using the flow cytometry to detect the percentage of CD3⁺、 CD3⁺CD4⁺、 CD3⁺CD8⁺、 CD3^-CD16+56⁺、 CD3⁺CD16+56⁺ cells in lymphocyte,and then comparing their percentage before the expansion in vitro.Results: After cell culture,the percentage of CD3⁺,CD3⁺CD8⁺,CD3⁺CD16+56⁺ cells increased greatly（P＜0.01）,and the percentage of CD3⁺CD4⁺ and CD3^-CD16+56⁺ cells decreased obviously（P＜0.01）.There were no obvious side reactions on patients after transfusion.Conclusion: The induction and enlarged proliferation efficiency of NK cells and sensitized lymphocyte from malignant tumor patients' peripheral blood under this culture system is pretty high,the percentage of cytotoxic cells in lymphocyte increases greatly,and lymphocyte after proliferation are of good biologic security.