Objective: To investigate the expression level of programmed death factor 1 (PD-1) in non-small cell lung cancer and its clinical significance. Methods: A retrospective analysis of 86 tissue specimens of non-small cell lung cancer and 60 adjacent normal lung tissue specimens from May 2014 to December 2015 in our hospital after resection and histopathological or cytological examinations, using the immune group The SP method was used to detect the expression of PD-1 in the tissues and analyze its relationship with clinicopathological characteristics. A total of 86 patients were followed up after surgery for 5 years to analyze the relationship between PD-1 and prognosis. Results: the positive expression of PD-1 protein was mainly located in the infiltrating lymphocyte membrane and cytoplasm in the tumor stroma, showing brownish yellow granules. In 86 cases of non-small cell lung cancer, the positive expression rate of PD-1 was 65.12%. PD-1 positive expression rate was 8.33% in 60 cases of adjacent normal lung tissues. Compared with adjacent normal lung tissues, the level of PD-1 positive cells in non-small cell lung cancer was significantly higher, with statistically significant difference (P<0.05). There was no significant correlation between PD-1 expression and gender, age, tumor diameter, invasion depth and differentiation degree of non-small cell lung cancer (P>0.05), but there was a close correlation between PD-1 expression and lymph node metastasis and TNM stage (P<0.05). The median survival time of patients with PD-1 negative expression and PD-1 positive expression was 28.9 months and 50.7 months, respectively. Compared with patients with PD-1 positive expression of non-small cell lung cancer, the survival time of patients with PD-1 negative expression of non-small cell lung cancer was significantly longer and the difference was statistically significant (P<0.05). Univariate analysis showed that tumor survival was not related to gender, age, tumor differentiation and invasion depth, but was closely related to TNM stage and lymph node metastasis (P<0.05). The results of multivariate analysis of survival time of non-small cell lung cancer patients showed that TNM stage, lymph node metastasis and PD-1 positive expression were important influencing factors of non-small cell lung cancer patients, with statistically significant differences (P<0.05). Conclusion: PD-1 positive cells in non-small cell lung cancer present high expression level, and there is a certain correlation between the expression level of PD-1 and the clinicopathological characteristics, which helps to indicate the changes in the disease development of non-small cell lung cancer, and is conducive to the judgment of prognosis and prognosis of patients.