Objective To evaluate the efficacy and adverse effects of the three dimensional conformal radia- tion therapy(3D-CRT) concurrently combined with chemotherapy for limited stage small cell lung cancer(LSCLC). Methods 33 patients with LSCLC received 6 cycles EP(cisplatin,etoposide) chemotherapy and 3 weeks was a cy- cle. The conventional radiotherapy was given after the first cycle chemotherapy or the third cycle chemotherapy, then the 3D-CRT and the total dose of the primary tumor was 45Gy per 3 weeks,1.5Gy for once,twice for a day. Results Toxicity was durable in 33 patients received 3D-CRT concurrently combined with chemotherapy. The total re- sponse was 97 %. Median time was 21.9 months, and the 1-,2-, 3-year survival rates was 69.7 % ,51.5 %, 30.3 %. The 1-,2-, 3-year local progress ion-freely survival rates were 66.7 %, 45.5 %, 30.3 %, respectively, with the median local progression-freely survival time of 18.5 months. Respectively during three year follow-up visit. Conclusion The 3D-CRT concurrently combined with chemotherapy for patients with limited stage small cell lung cancer could be more effectively, and the patients could tolerate the side effects, this therapy method was secure and received.