Objective To evaluate the diagnostic value of preoperative positron emission computed-tomography(PET-CT)examination for lymph node metastasis in early non-small cell lung cancer(NSCLC).Methods A total of 232 early-stage NSCLC patients who underwent preoperative PET-CT examination and radical surgery for lung cancer in the hospital from January 2019 to April 2023 were selected.Clinical data,PET-CT examination results,and lymph node dissection pathology were collected to calculate the sensitivity,specificity,accuracy,positive predictive value and negative predictive value of PET-CT diagnosis of NSCLC lymph node metastasis.The maximum standard uptake value(SUVmax)of the primary lesion and the predic-tive value of lymph node SUVmax for early NSCLC lymph node metastasis were evaluated by the receiver op-erating characteristic(ROC)curve.Results The accuracy of PET-CT examination in the diagnosis of NSCLC was 95.69％,the accuracy of lymph node metastasis diagnosis was 85.78％,the sensitivity was 35.56％,the specificity was 97.86％,the positive predictive value was 80.00％,and the negative predictive value was 86.32％.There was a statistically significant difference in the detection rate of PET-CT examination and path-ological results among pulmonary nodules of different natures and sizes(P＜0.01).For predicting lymph node metastasis in NSCLC,the cutoff point of SUVmax in the primary lesion was 3.83(P＜0.001),and the cutoff point of SUVmax in lymph nodes was 3.07(P＜0.001).Conclusion In early NSCLC,preoperative PET-CT examination has a high diagnostic accuracy for ground glass nodule lymph node metastasis,but its di-agnostic value for solid nodule lymph node metastasis is limited and insufficient to guide lymph node dissec-tion.Primary lesion SUVmax≥3.83 or lymph node SUVmax≥3.07 are high-risk factors for early lymph node metastasis in lung cancer.