Abstract: ［Abstract］Objective　To observe the protective effect of long acting sterile antibacterial materials on skins of patients with nasopharyngeal carcinoma after intensity modulated radiotherapy（IMRT）．Methods　104 patients with nasopharyngeal carcinoma who received first intensity modulated radiotherapy were randomly divided into 2 groups: the observation group and the control group．Long-acting sterile antibacterial material was prophylactically sprayed on local skins of 56 patients in observation group after the first radiotherapy for 4 times/day．48 patients in the control group were only given keeping clean and dry in the local skin. Patients in both groups were given routine skin care and health education．Results　In the observation group and the control group，the incidence rate of Ⅱand Ⅲ radiodermatitis was 28.5% and 66.7%，respectively．The serious degree of radiodermatitis in patients in observation group was less than that in control group，and the incidence of radiodermatitis in patients in observation group was later than that in control group，and the difference was statistically significant（P＜0.05）．Conclusion　Long acting antibacterial materials can effectively prevent the occurrence of radiodermatitis，reduce the degree of skin damage， improve the life quality of patients and ensure smooth accomplishment of radiation therapy.