Abstract: Objective To analyse clinical efficacy of intensity modulated radiation therapy (IMRT) for primitive nasopharyngeal carcinoma (NPC). Methods From Jun 2006 to Aug 2008, 128 patients with NPCunderwent IMRT at our hospital. According to the 1992 Fuzhou Staging Classification, there were 2patients in stageⅠ,19 instageⅡ,58 instage Ⅲ and 49 in stage Ⅳa. The prescription dose was (70~74) Gy/30f to the nasopharynx gross tumor volume(GTVnx), (68~70)Gy/30f to positive neck lymph nodes (GTVnd), (60~64)Gy/30f to the first clinical target volume (CTV1) and (50~54)Gy/30f to the second clinical target volume (CTV2). Kaplan-Meier method was used to calculate the overall survival rate(OS),distant metastasis-free survival rate(DMFS),and local-regional control rates from the last day of therapy. Log-rank test was used to detect the difference between groups. Results The median follow-up interval was 12 month (6 ~24 months). The l-year and 2-year OS were 100% and 96.9%, DMFS were 92.2% and 88.3%, the local-regional control rates were 96.1% and 93.8%, respectively. Lymph node staging was the most important prognosis factor in affecting disease metastasis free survival rate ( P =0.04). The most serious acute toxicity was mucositis with GradeⅠto Ⅳof38.8%,48.4%,7.8% and0 respectively. The late toxicity was mostly salivary gland with GradeⅠ 67.2% and GradeⅡ 19.5%. Conclusion IMRT could improve the target volume dose and decrease the dose of surrounding tissue resulting in higher control rate and lower side effect. IMRT is a safe valid method.N(+) is significantly correlated with distant metastasis.