〔Abstract〕 Objective To compare the dosimetric indexes between spiral tomography radiotherapy and static intensity modulated radiotherapy in fi xed fi eld for nasopharyngeal carcinoma. Methods 80 cases with nasopharyngeal carcinoma admitted to the first affiliated hospital of Bengbu medical college from January 2018 to December 2019 were randomly divided into two groups, 40 cases each. The target dose and organ-threatening dose were compared between the two groups. Results The d95 of TOMO gross tumor volume (PGTVnx), cervical metastatic lymph nodes (PGTVnd), subclinical lesions (PTV1) and radiation prevention area (PTV2) were signifi cantly lower than those of IMRT (P < 0.05), and the dose of Tomo endangering brain stem was signifi cantly lower than that of IMRT (P < 0.05). Conclusion The plans of Tomotherapy group and intensity-modulated group can be used in clinic, but Tomotherapy group has more obvious advantages in dose distribution in radiotherapy, lower dose of endangered organs and better protection of normal tissues.