This study evaluated the diagnostic efficiency of 68Ga-FAPI-04 PET/CT in detecting lymph node metastasis in non-small cell lung cancer (NSCLC) and its correlation with fibroblast activation protein (FAP) expression. A total of 136 participants with suspected or biopsy-confirmed NSCLC underwent 68Ga-FAPI-04 PET/CT for initial staging. Of these, 91 participants were analyzed, with 91 primary tumors evaluated. The diagnostic sensitivity and positive predictive value of 68Ga-FAPI-04 PET/CT for detecting the primary tumor were 96.70% and 100%, respectively. In station-based analysis, the diagnostic sensitivity, specificity, and accuracy for detecting lymph node metastasis were 72.00%, 93.10%, and 89.36%, respectively. Tumor 68Ga-FAPI-04 uptake (SUVmax, SUVmean, FTV, and TLF) correlated positively with FAP expression (r = 0.470, 0.477, 0.582, and 0.608, respectively; all P ≤ 0.001). The volume parameters FTV and TLF correlated strongly with FAP expression in 31 surgical specimens (r = 0.700 and 0.770, respectively; both P < 0.001). The study concluded that 68Ga-FAPI-04 PET/CT had excellent diagnostic efficiency for detecting lymph node metastasis, and 68Ga-FAPI-04 uptake showed a close association with FAP expression in participants with NSCLC. The results suggest that 68Ga-FAPI-04 PET/CT may be a valuable alternative tracer for imaging NSCLC, and 68Ga-FAPI-derived volume parameters may be potential predictors of FAP-targeted radioligand therapy in patients with advanced NSCLC. The study had some limitations, including the lack of histopathologic evidence for some distant metastatic lesions and a relatively small sample size for FAP immunostaining subgroups. Further large-scale multicenter prospective clinical trials are required to validate the current findings regarding 68Ga-FAPI-04 in NSCLC.This study evaluated the diagnostic efficiency of 68Ga-FAPI-04 PET/CT in detecting lymph node metastasis in non-small cell lung cancer (NSCLC) and its correlation with fibroblast activation protein (FAP) expression. A total of 136 participants with suspected or biopsy-confirmed NSCLC underwent 68Ga-FAPI-04 PET/CT for initial staging. Of these, 91 participants were analyzed, with 91 primary tumors evaluated. The diagnostic sensitivity and positive predictive value of 68Ga-FAPI-04 PET/CT for detecting the primary tumor were 96.70% and 100%, respectively. In station-based analysis, the diagnostic sensitivity, specificity, and accuracy for detecting lymph node metastasis were 72.00%, 93.10%, and 89.36%, respectively. Tumor 68Ga-FAPI-04 uptake (SUVmax, SUVmean, FTV, and TLF) correlated positively with FAP expression (r = 0.470, 0.477, 0.582, and 0.608, respectively; all P ≤ 0.001). The volume parameters FTV and TLF correlated strongly with FAP expression in 31 surgical specimens (r = 0.700 and 0.770, respectively; both P < 0.001). The study concluded that 68Ga-FAPI-04 PET/CT had excellent diagnostic efficiency for detecting lymph node metastasis, and 68Ga-FAPI-04 uptake showed a close association with FAP expression in participants with NSCLC. The results suggest that 68Ga-FAPI-04 PET/CT may be a valuable alternative tracer for imaging NSCLC, and 68Ga-FAPI-derived volume parameters may be potential predictors of FAP-targeted radioligand therapy in patients with advanced NSCLC. The study had some limitations, including the lack of histopathologic evidence for some distant metastatic lesions and a relatively small sample size for FAP immunostaining subgroups. Further large-scale multicenter prospective clinical trials are required to validate the current findings regarding 68Ga-FAPI-04 in NSCLC.