Abstract： Objective To observe the toxicity and effection of three dimensional conformal radiation therapy(3DCRT)based on conventional fractionation radiotherapy in combination with chemotherapy in non-small-cell lung cancer(NSCLC).Methods 62 NSCLC patients with stage Ⅲ were chosen as research objects.All the patients received chemotherapy two cycles with NP regimen firstly(NVB 40 mg d1,8,DDP 30 mg d2-5),then they accepted radiotherapy in twentith day after chemotherapy when hemocyte got normal.In the first half period of the radiotherapy,conventional radiotherapy were given with 2 Gy/f,after the dose got 40 Gy/20 f,then three dimensional conformal radiation therapy were given with 4～6 Gy/f every 1 to 2 days until the total dose got 24～30 Gy/4～6 f.The patients with supraclavicular lymphnode metastatic carcinoma received conventional fractionation radiotherapy with 60Co or 6 MV-X ray combined electronic ray until the dose(DT)up to 64～66 Gy.After radiotherapy,the patients accepted chemotherapy two cycles with NP regimen again.Results All the 62 patients completed treatment plan,and follow-up survey had lasted for 3 years.The short-term efficacy was evaluated in 3 months after radiotherapy. Among 62 patients, 9 cases gained a complete remission(CR),40 cases partial remission(PR),and the total remission was 79.0%.The acute toxicity showed acute radiation esophagitis,radiation pneumonia and acute gastrointestinal reaction.However,expectant treatment was effective.The 1,2,3 year survival rate was 7 1.0%,48.4%,30.6%,respectively.The 1,2,3 year local control rate was 80.6%,62.9%,40.3%,respectively.Conclusion 3DCRT based on conventional fractionation radiotherapy for NSCLC have good effection and mild toxicity.