Abstract: Objective : To investigate the diagnosis and surgical therapy of second primary lung cancer (SPLC). Methods : The clinical materials and pathological section of patients with SPLC between 1985 and 1999 were reviewed. For definitive diagnosis, P53 P16 nm23 bcl-2 genes were detected on the wax specimens of SPLC has same histologically. Results : 24 patients with SPLC were found in 2223 patients with lung cancer receiving the surgical therapies. SPLC were synchronous with primary tumor in 11 cases and metachronous in 13 cases. Squamous cell carcinoma accounted for 50%(12/24) of all patients with SPLC, Whereas, adenocarcinma com-prised 31.5% (9/24), small cell 4.2%, large cell 4.2%, and adeno-squamous-cell 4.2%. Histol-ogy of the SPLC was the same as that of the first tumor in 12 cases and the others were the different. As for location, the second tumor was ipsilateral with the primary tumors in 10 cases and contralateral in 14 cases. Five-year survival for patients with synchronous and metachronous SPLC receiving surgical therapy were 29% and 23% respectively. Patients with stage I Ⅱ Ⅲ diseases were found having 40%, 16.7% and zero 5-yr survivorship.In patients with curative and stage resection the 5-yr survivals were 40% and 12.5% respectively. Conclusion : We suggest that the gene detection apply to diagnosis of SPLC.The teratments of SPLC were equal to primary lung cancer.