Objective:To study correlated factors of oral mucositis caused by radiotherapy in nasopharyngeal carcinoma patients with intensity modulated radiotherapy,in order to standard particular nursing steps and reduce the incidence of serious radiogenic stomatitis. Methods:One hundred and fifty patients were investigated and 12 indexes were analyzed by ?字2 text. Results:All the patients suffered oral mucositis,Ⅱ and above oral mucositis were about 81%. Single factor analysis found that nutrition,smoking,dental heath,oral pH,antibiotics using and chemotherapy were correlated with oral mucositis. Conclusion:Attention should be paid to the patients receiving intensity modulated radiotherapy especially with smoking, antibiotics using and chemotherapy. Preventive nursing during radiogenic or after radiogenic should be strengthened to reduce the incidence and severity of oral mucositis.