〔Abstract〕 Objective The study aimed at exploring the expression level and clinical significance of miR-22 in serum of patients with non-small cell lung cancer. Methods 276 patients with NSCLC diagnosed were collected.The expression of miR-22 in serum was detected by qRT-PCR,and its correlation with clinical features and prognosis was analyzed. Results The serum level of miR-22 in NSCLC patients was higher than that in normal subjects(P<0.01).According to the different clinical characteristics of NSCLC patients, we could know that the expression of miR-22 was different in M stage, N stage, tumor differentiation degree, lung cancer bone metastasis, lung cancer liver metastasis and intrapulmonary metastasis groups(P<0.05).High level group and low level group were divided according to the average level of serum miR-22 in NSCLC patients, and the expression of serum miR-22 was correlated with N stage, M stage, liver metastasis and intrapulmonary metastasis of lung cancer.Survival analysis showed that the prognosis of NSCLC patients with low serum miR-22 expression was better than that of the patients with high serum miR-22 expression(P<0.05).Multivariate Cox analysis confirmed that serum miR-22,T stage, M stage, bone metastasis of lung cancer and primary tumor laterality were independent prognostic factors of NSCLC patients. Conclusion The expression of serum miR-22 is closely related to the occurrence and development of non-small cell lung cancer patients, which can be used as an independent prognostic factor for NSCLC patients.