Objective To study the effects of PET/CT on the clinical stages of patients with non-small-cell lung cancer (NSCLC) and to analyze its application value in the prognosis of patients. Methods The clinical data of 172 patients with NSCLC surgery from June 2011 to June 2013 were retrospectively analyzed retrospectively. The results of postoperative pathological examination were used as the gold standard to analyze the accuracies of 18F-FDG PET/CT in the detection of primary tumors, peripheral lymph nodes and distant metastasis, and the SUVmax of primary lesion was calculated and its effects on postoperative long-term survival were analyzed. Results The accuracy rate of PET/CT was 93.60% in the detection of preoperative T staging of NSCLC primary lesions. The sensitivities of preoperative detection of N1, N2 lymph nodes and distant metastasis were 88.16%, 93.10% and 92.59%, and the specificities were 79.17%, 81.57% and 81.37%, and the accuracy rates were 83.14%, 85.47% and 83.14%, and the consistency Kappa values were 0.663, 0.697 and 0.537.The SUVmax range was 3.2 to 37.1 among 172 patients with NSCLC with a median of 12.4. SUVmax=12.4 was used as the critical value to divide the patients into two groups. Log-rank test showed that the DFS and OS of patients with SUVmax≤12.4 were higher than those of patients with SUVmax >12.4 (χ2 =3.864, 4.889, P<0.05). Conclusion PET/CT for preoperative examination of NSCLC can improve the accuracy of TNM staging, and can also use SUVmax value to evaluate the prognosis of patients, and it provides an important basis for clinical selection of reasonable treatment regimens.