Objective To investigate the significance of detecting circulating tumor cells(CTCs) in peripheral blood of postoperative patients with non-small cell lung cancer(NSCLC). Methods Thirty-eight patients with lung adenocarcinoma diagnosed by pathology and treated by radical surgery, were staged by TNM staging criteria,including stage Ⅰ 19 cases, stage Ⅱ 6 cases, and stage Ⅲ 13 cases. Ten patients with lung benign disease served as control group; they were diagnosed by postoperative pathology(4 cases with tuberculosis, 6 cases with lung inflammatory lesions). CTCs in peripheral blood(every 7.5 ml)were detected by the method of immune magnetic bead-based rare cell enrichment system combined with flow cytometry. Results The positive rate of peripheral blood CTCs was 10%(1/10)in lung benign disease patients and 39.5% (15/38) in NSCLC patients. There was no difference in CTCs positive rate between lung benign disease patients and NSCLC patients(P=0.132).There was difference in CTCs positive rate between Ⅰ stage patients and Ⅲ stage patients(χ²=3.970,P=0.046). Conclusions CTCs can be detected in peripheral blood of postoperative NSCLC patients and can be used to guide the therapy.The positive rate of CTCs is related to TNM staging.