Objective To study the application value of 18F-FDG PET-CT combined with chest breath-hold spiral CT in the diagnosis of preoperative TNM staging of non-small cell lung cancer (NSCLC). Methods A total of 62 cases of patients with NSCLC admitted to our hospital were selected for the study. The results of pathological examination were used as the gold standard to evaluate the application value of 18F-FDG PET-CT and chest breath-hold spiral CT in preoperative staging of NSCLC. Results Among the 62 patients, the accuracy of CT-T staging was 80.65% (50/62), and the accuracy of 18F-FDG PET/ CT-T staging was 64.52% (40/62), and there was a significant difference in the accuracy of T staging between the two groups (P<0.05). The accuracy of CT-T staging was 14.29% (1/7) in patients with central lung cancer and obvious obstructive changes, and the accuracy of 18F-FDG PET/CT-T staging was 71.43% (5/7), and the difference in correct diagnosis rate was significant between the two groups (P<0.05). The accuracy of CT density-N staging was 67.84%, and the accuracy of uptake-N staging was 69.35%, and the accuracy of CT density and uptake-N staging was 77.42%, and there was no significant difference in the accuracy of N staging among the groups (P>0.05). The accuracy of CT-M staging was 91.94%, and the accuracy of 18F-FDG PET/CT-M staging was 98.39%, and there was no significant difference in the accuracy of M staging between the two groups (P>0.05). The accuracy of CT-TNM staging was 80.65%, and the accuracy of 18F-FDG PET/CT+CT-TNM staging was 91.94%, and there was no significant difference in accuracy of TNM staging between the two groups (P>0.05). Conclusion CT and 18F-FDG PET/CT can effectively improve the accuracy of preoperative staging of patients with NSCLC.