This paper is the exploration and analysis of the diagnostic value of circulating tumor cells (CTC) and circulating tumor deoxyribonucleic acid (ctDNA) in early non-small cell lung cancer (NSCLC).A total of 125 NSCLC patients that hospitalized from March 2019 to December 2020 were selected, of which 64 subjects with stage I-II were listed as the early-stage group, and 61 patients with stage III-IV were classified as the intermediate-advanced group; In addition, 47 patients with benign pulmonary nodules hospitalized within same period were selected as a group of benign pulmonary nodules, and 50 healthy subjects were enrolled as a control group. The levels of CTC and ctDNA, serum tumor markers carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), cytokeratin 21-1 (CYFRA21-1) and gastrin-releasing peptide precursor (pro-GRP) were detected. The diagnostic value of CTC and ctDNA in early NSCLC patients was analyzed by ROC curve. The area under the curve of CTC count for early-stage lung cancer was 0. 949 (P=0. 000, 95%CI: 0. 918-0. 980), and ctDNA was 0. 914 (P=0. 000, 95%CI: 0. 866~0. 963). There were significant differences in CTC count and ctDNA among subjects in each group (P<0. 05). CTC count and ctDNA of the early and intermediate-advanced group were remarkably higher than those of the control group and group of benign pulmonary nodules (P<0. 05), and CTC count and ctDNA of patients in the middle-late group were critically higher than those in the early-stage group (P<0. 05). There were significant differences in serum CEA, NSE, CYFRA21-1 and pro-GRP levels among all groups (P<0. 05). The results showed that CTC and ctDNA in NSCLC patients were significantly positively correlated with CEA, NSE, CYFRA21-1 and pro-GRP (P<0. 05). Peripheral blood CTC and ctDNA levels are significantly increased in NSCLC patients. They are positively correlated with serum tumor markers CEA, NSE, CYFRA21-1 and pro-GRP levels, and are related to tumor progression. CTC and ctDNA have high value in the clinical diagnosis of early NSCLC.