Objective：To determine the accuracy and the role of bronchoscopic radioisotope injection technique for detecting the sen－tinel lymph node（SLN） in patients with non-small cell lung cancer. Methods：Twenty patients with resectable non-small cell lung cancer（NSCLC） were included. A dosage of 18.5-55.5 MBq 99Tcm-labeled sulfur colloid was endoscopically administrated for pa－tients before anesthesia. The radioactivity of primary tumor and background was gathered after thoracotomy with a hand-hold gamma probe. Patients underwent routine lung resection and mediastinal lymphadenectomy. Radiolabeled nodes were also examined in vitro separately. Routine pathological examination was implemented and immunohistochemistry（ICH） was carried out for micrometastases. Results：Identification of SLNs was in 17 patients. In 12 patients，a unique SLN was identified and in 3 patients two SLNs were de－tected，whereas in two patients，nodes from three different stations could be classified as SLNs. The sensitivity and specificity were 5３%（9/17） and 100%（3/3）. Conclusion：Using bronchoscopic radioisotope injection technique to identify sentinel lymph node in patients with NSCLC is reliable. It could be a physiological way to map SLN.