Objective To investigate the effects of the radical resection of lung cancer combined with 125 I implantation. Methods Fifty-two cases of non-small cell lung cancer ( NSCLC) in stageⅠB-ⅢA were randomly divided into observation group and control group,27 and 25 cases respectively. Patients in both groups were performed with radical resection of lung cancer and four cycles of chemotherapy,and 125 I was implanted in the mediastinal lymphatic drainage area only in observation group. Local tumor control rate and tumor markers levels,like CEA,CA125,CA153,CA199,of the two groups in different period were measured and compared. Results Three months after operation,the tumor markers levels in each groups decreased significantly compared with pre-operation( P < 0. 05) . There was no differences in preoperative or postoperative tumor markers levels between two groups or within each group in each periods. But,12 months after surgery,for patients with mediastinal lymph node micrometastasis,the tumor local control rate in the observation group ( 89. 47%) was higher than that in the control group ( 56. 26%) ,which was statistically significant ( P < 0. 05) . Conclusions For patients with mediastinal lymph node micrometastasis,lung cancer radical operation combined with 125 I implantation could prolong tumor-free survival period and decreased the risk of local recurrence.