Abstract: Objective To explore the expression characteristics of programmed death-1（PD-1） on CD8+T in the peripheral blood from patients with non-small cell lung cancer （NSCLC） as well as the relationship between level of PD-1 and clinicopathologic variables. Methods Ninety NSCLC patients， including 50 squamous cell carcinoma and 40 adenocarcinoma， and thirty healthy controls were selected. CD8+T cells were obtained from the peripheral blood mononuclear cells. The positive expression ratio of the PD-1 on the CD8+T cell surfaces in the peripheral blood was detected using flow cytometry. We then analyzed the relationship of PD-1 expression with age， gender， pathological classification， clinical stage， pathological degree and lymphatic metastasis. Results The positive expression ratio of PD-1 on CD8+T cell in the peripheral blood of the three groups were （18.32±5.20）%， （18.68±5.41）% and （7.44±2.59）%， and the data of NSCLC patients was higher than that of the healthy controls （F=58.344， P＜0.001）.The results were obviously related to the clinical stage and lymphatic metastasis （P＜0.05）， which positively correlated with the clinical stage of the NSCLC （rs=0.875， P＜0.001）. However， no difference was observed on age， gender， pathological classification and pathological degree （P＞0.05）. Conclusion The positive expression ratio of PD-1 on CD8+T cell in the peripheral blood of NSCLC patients was higher than that of the healthy controls， and the high expression ratio of PD-1 on CD8+T cell were significantly related to the clinical stages and lymphatic metastasis. The elevated level of PD-1 might be related with the immune escape of the NSCLC， thus playing a crucial role in the occurrence and development of NSCLC.