Abstract: Objective:To predict survival outcome, the lymphocyte subsets between lung cancer patients and healthy subjects was compared, and the significance of T-lymphocyte subgroups and NK cell base amount in the peripheral blood of lung cancer patients was evaluated.Methods:The percentage of CD 3+T, CD4+T, CD8+T, and natural killer (NK) cells in the peripheral blood of 105 patients with lung cancer and 35healthy subjects were analyzed by flow cytometry. Among the105 patients, 19cases were small cell lung can-cer (SCLC) and 86cases were non-small cell lung cancer (NSCLC). The lymphocyte levels of the subgroups were recorded, and the rela-tionship between lymphocyte subsets of 86NSCLC patients and survival outcome was analyzed retrospectively. Results:The levels of CD3 +, CD 4+, NK cells and the ratio of CD 4/CD 8 in patients have respective P values of 0. 011 , 0. 007 , <0. 001 , 0. 025 , which were signifi -cantly lower than that in normal subjects. However, the proportion of CD 8+ increased remarkably in patients ( P=0. 013 ). The overall sur -vival (OS) was more longer when CD 8+ T were ≥ 31. 8% of NSCLC patients, and the ratio of CD4/CD 8 were less than 1. 28of NSCLC pa -tients (mean OS 36. 2 m vs . 20. 0 m,P=0. 010 ; 30. 8 m vs . 20. 0 m,P=0. 035 , respectively). However, the percentage of CD 3+, CD 4+, and NK cells had an insignificant effect in predicting the prognosis of NSCLC patients. Conclusion: High basal levels of CD8+T cells in peripheral blood could prolong the survival of patients with NSCLC. Furthermore, evaluating the basal levels of CD 8+T cells by flow cytometry in peripheral blood might provide prognostic information.