Abstract: Objective : To study the prognostic significance of PSA overexpress in resected squamous cell lung cancer. Methods : 139 squamous cell lung cancer patients underwent radicalresection from 1995.01~1997.12 in this hospital were followed. Of which 126 patients replied. All sections from each specimen were stained with immunohistochemical SABC method. Results : PSA was expressed in 30 of 126 (23.8%) patients, all of them were stage---a patients,and the relationship of PSA expression was not related with TNM (P>0.05). The 5-year survival rate for those with PSA-positive and PSA-negative cases were 33.3% and 53.1% respectively, there were no significant difference (P>0.05). As for the patient of stage I , the 5-year survival rates for those with PSA-positive and PSA-negative tumors were 42.9% and 84.6% (P<0.05), and for p-stage patients those were 20.0% and 64.5% respectively. It significantly demonstrated a worse prognosis for the p-stage I and p-stage PSA-positive patients. Additionally, there proved to be no difference in the postoperative survival among p-stage I , II and III a patients when PSA expression was positive (P>0.05). Conclusion : Statistical analysis confirmed that the PSA expression was an independent factor to predict a poor prognosis in resected p-stage Iand II squamous cell lung cancer patients.