OBJECTIVE: To further investigate the accuracy and specificity of PET/CT in the diagnosis of benign and malignant lung occupational diseases. METHODS: We reviewed 298 patients who underwent pulmonary resection in our department, who had preoperative whole-body or chest PET/CT examinations, and compared and evaluated the diagnostic value of PET/CT in identifying benign and malignant by using postoperative pathological findings as the gold standard. RESULTS: In our group of patients, the final pathology confirmed 248 malignant lesions and 50 benign lesions. the sensitivity of PET/CT in diagnosing benign and malignant lung lesions was 80.2%, the specificity was 38%, the positive predictive value was 86.5%, the negative predictive value was 27.9%, and the overall accuracy was 73.1%. the invisible predictive value and specificity of PET/CT were low. The area under the PET/CT curve (AUC) evaluated by subject characteristic curve (ROC) analysis was 0.694. Among 219 patients with non-small cell lung cancer, 43 patients had false-negative PET/CT results. Multifactorial risk analysis revealed highly differentiated, peripheral type lesions, absence of pleural invasion, tumor less than 75 px, adenocarcinoma, and nonsmoking as independent risk factors for the occurrence of false negatives. CONCLUSION: Our present study suggests that the value of PET/CT in identifying benign and malignant lung lesions may be overestimated.