Objective To analyse the relationship between T lymphocyte subsets and NK cells expression and dynamic changes in lung cancer patients 'peripheral blood and the occurrence and development of cancer,and investigate their clinical significances.Methods Flow cytometry was applied to detect 66 patients with lung cancer,60 patients with pulmonary tuberculosis and 60 healthy persons peripheral blood CD+3,CD+3CD+8,CD+3CD+4,Th/Ts,CD+16CD+56 expression.Lung cancer group peripheral blood CD+3,CD+3CD+8,CD+3CD+4,Th/Ts,CD+16CD+56 expression were also detected on 3rd,7th and 20th day before and after chemotherapy.Results Lung cancer group CD+3,CD+3CD+4,Th/Ts,CD+16CD+56 expression decreased significantly [(54.23±10.37)％,(34.23±8.03)％,1.35±0.20,(25.18±4.34)％] and had significant differences compared with pulmonary tuberculosis group [(63.09±9.19)％,(39.46±12.74)％,1.51±0.41,(26.45±3.96)％] and healthy group [(69.68±8.31)％,(42.31±13.29)％,1.89±0.48,(29.44±2.51)％](P ＜ 0.05),but CD+3CD+8 expression showed no significant difference(P ＞ 0.05).In chemotherapy group,comparing with before chemotherapy,remission group CD+3,CD+3CD+4,Th/Ts and CD+16CD+56 expression decreased significantly (P ＜ 0.01)on 3rd day after chemotherapy,while CD+3CD+8expression increased significantly(P ＜ 0.01).On 7th day,each index recovered to the level of before chemotherapy basically.On 20th day,CD+3,CD+3CD+4,Th/Ts and CD+16CD+56 expression increased significantly(P ＜ 0.05)compared with before chemotherapy,while CD+3CD+8 expression significantly decreased(P ＜ 0.05).Chemotherapy unease group had no significant difference (P ＞ 0.05).Lung cancer of stage Ⅲ A and Ⅲ B compared with stage Ⅰ A,and lymph node metastasis in N3 group compared with N0 group,CD+3,CD+3CD+4,CD+3CD+8,Th/Ts and CD+16CD+56 expression had significant differences (P ＜ 0.05).Compared with their pathological types,each index had no significant difference(P ＞ 0.05).Conclusion Monitoring the peripheral blood T lymphocyte subsets and NK cells dynamic of lung cancer patients can guide the clinical diagnosis and treatment,and contribute to the assessment of immune function.