Abstract: Objective To investigate the clinical application of combined detection of squamous cell carcinoma antigen(SCC), neuron-specific enolase(NSE), carcinoembryonic antigen(CEA)and cytokeratin 19 fragment antigen 21-1(CYFRA21-1)in diagnosis of lung cancer. Methods A total of 41 patients with lung cancer and 41 patients with benign tumor were separately selected as lung cancer group and benign group. Another 41 healthy people with physical examination were selected as healthy group. Serum CEA, NSE, SCC and CYFRA21-1 levels of three groups were compared. The specificity, sensitivity and accuracy of combined tests of four indicators and single test in diagnosis of lung cancer were analyzed. Results The serum NSE, SCC, CEA and CYFRA21-1 levels in the lung cancer group were significantly higher than those of the benign group and the healthy group(P<0.05); the NSE, SCC, CEA and CYFRA21-1 levels in the benign group and the healthy group showed no significant differences(P>0.05). The specificities of single detection and combined detection in diagnosis of lung cancer were both higher, but no significant differences were found(P>0.05). The sensitivity and accuracy of combined detection of NSE, SCC, CEA and CYFRA21-1 were 95.12% and 93.50% respectively, which were significantly higher than those of single detection(P<0.05). Conclusion Combined detection of NSE, SCC, CEA and CYFRA21-1 levels has higher accuracy and sensitivity in the diagnosis of lung cancer, which can effectively distinguish benign lung lesions from lung cancer, and it is of great value in clinical diagnosis.