Abstract: Abstract :Objective 　The current study was designed to determine the dose-limiting toxicities and clinical practicable of radiotherapy with Topotecan for local advanced non-small cell lung cancer. Methods 　Sixteen patient s with histologically confirmed diagnosis of local late-stage NSCLC, radiotherapy include primary tumor site of lung and the area of lymph node. Patient s were treated with Topotecan at three dose level (0. 5mg/ m², 0. 75mg/ m² and 1mg/ m² ) while the radiotherapy started. Topotecan was given intravenously twice a week over total four weeks . Dose escalation was based, on each level, of a minimum of three patient s in cohort if severe toxicity had not been observed until the maximum tolerance dose (MTD) . Results 　The predominant form of toxicity is hematologic toxicity and radiation esophagitis. The MTD was 0. 75mg/ m² . Conclusion 　Combined radiotherapy and Topotecan for t reatment of local late-stage NSCLC is well tolerant . We recommend that the dose for phase II clinical t rial is 0. 5mg/ m² .