Abstract: Objective To evaluate the outcome of locally advanced non-small cell lung cancer treated with radiotherapy and chemotherapy.Methods From July 2001 to December 2006,83 patients with locally advanced non-small cell lung cancer were enrolled.Three groups were divided based on time and sequence of radiotherapy and chemotherapy.All patients used three dimensional conformal radiation therapy and cisplatin based chemotherapy.The short-term response and 1-year,2-year survival rates,median survival time and toxicity in three groups were compared.Results The overall response in three groups were 89.3%,78.1% and 68.5%(P＞0.05)respectively.The median survival time were 21 months,18 months and 16 months,respectively,The 1-,2-year survival rate were 75%,67.86%,51.16% and 49.01%,44.44%,31.97%(P＜0.05)respectively for three groups.And the differences of toxicity rates for three groups were not statistically significant.Conclusion Induction chemotherapy followed by three dimensional conformal radiation therapy was efficacy and safety.The sequential chemoradiotherapy improved the overall survival of locally advanced non-small cell lung cancer.The output indicated early irradiation with chemoradiotherapy is superior to late irradiation.Induction chemotherapy is optimization for one or two cycles.