Abstract: ObjectiveTo analyze the dosimetric differences and evaluate the clinical efficacy and acute side reaction of box technique and intensity modulated radiation therapy（IMRT）in whole pelvic radiotherapy of stage ⅡB cervical carcinoma. Methods CT simulation was given to 10 pathologically confirmed patients with stage ⅡB cervical carcinoma. 3D TPS was used to make box technique plan and three IMRT plans with different fields’ distribution for each patient. Dose-volume histogram（DVH）was shown to evaluate planning target volume（PTV）and organs at risk（OAR）. A total of 77 patients with stage ⅡB cervical carcinoma from January 2011 to October 2012 were divided into box technique group with 33 patients and IMRT group with 44 patients according to their own wishes， and were treated with box technique or 9-filed IMRT associated with intracavitary irradiation and concurrent chemotherapy consisted of cisplatin per week. Clinical efficacy and acute side reaction were analyzed retrospectively. Results Conformity index（CI） and homogeneity index（HI） in three IMRT plans were better than those in box technique plan（P＜0.05）. V30 and V40 of the bladders， V20， V30， V40， Dmean， D50 of the small bowel， and V30， V40， Dmean， D50 of the rectum in three IMRT plans were lower than those in box technique plan（P＜0.05）. There were no differences in CI and HI of the three IMRT plans. With the increase of the radiation fields in the IMRT plans， V30， V40， Dmean， D50 of the bladder and V20， V30， V40， Dmean， D50 of the rectum were decreased gradually. The differences of V30， V40of bladder were statistically significant（P＜0.05）. Complete remission rate of box technique group was 84.8％，while the ratio of nine-filed IMRT group was 88.6％（P＞0.05）. The incidence of acute radiation enteritis and radiocystitis in 9-filed IMRT group were lower（P＜0.05）. All of the patients suffered bone marrow toxicity， but there was no significant difference between two groups（P＞0.05）.Conclusion Nine-field IMRT is recommended to patients with stage ⅡB cervical carcinoma as the protection for OARs is better both in the comparison of dosimetry and clinical efficacy.