Abstract: ［Abstract］Objective To explore the efficacy and safety of large and conventional fractionated three dimensional conformal radiation therapy for non small cell lung cancer with superior vena cava compression syndrome，and to provide clinical reference for improving the prognosis of patients with non small cell lung cancer. Methods The general data of 63 patients with non small cell lung cancer complicated with superior vena cava syndrome treated in Lu'an Hospital of Traditional Chinese Medicine from January 2010 to December 2012 were analyzed retrospectively. According to the different treatment methods， the patients were divided into observation group （n＝28）and control group（n＝35）.The control group was given conventional fractionated three-dimensional conformal radiation therapy，three dimensional conformal radiation therapy was given to the observation group. The clinical efficacy， toxicity， and 1，2 years survival rate of the two groups were compared. Results The complete remission rate of observation group was 96.43%， which was significantly higher than 74.29% in the control group（P＜0.05）. The complete remission in the observation group was 89.29% in two weeks， which was significantly higher than 62.86% in the control group （P＜0.05）. The total effective rate of observation group was 85.71%， which was significantly higher than that 62.86%in the control group （P＜0.05）. The clinical benefit rate of observation group was 96.43%， and there was no significant difference between the two groups （P＞0.05）. There was no significant difference in the incidence of adverse reactions between the two groups （P＞0.05）. There was no significant difference in 1，2 year survival rate between the two groups （P＞0.05）. Conclusion Three dimensional conformal radiation therapy for non small cell lung cancer patients with superior vena cava syndrome is superior to conventional treatment， and does not increase the toxic side effects， which is worthy of clinical attention.