Objective To investigate the treatment effects and toxicities of extended-field intensity modulated radiation therapy (EF-IMRT) and intra-cavitary brachytherapy combined with chemotherapy for stage Ⅰ b1-Ⅳa cervical cancer with positive para-aortic lymph nodes.Methods A total of 46 stage Ⅰ b1-Ⅳa cervical cancer patients with positive para-aortic lymph nodes treated at Fudan University Shanghai Cancer Center between 2009 and 2011 were reviewed.Neoadjuvant,concomitant and adjuvant chemotherapy with paclitaxel and carboplatin were administrated for one cycle before radiation therapy,two cycles during radiation therapy or three cycles after radiation therapy.All patients received EF-IMRT and intra-cavitary brachytherapy.The positive lymph nodes received an additional boost dose.Results All patients received EF-IMRT to 50.4 Gy (1.8 Gy per fraction).Twenty-six patients was treated with boost dose of 6.0-8.0 Gy in 2.0 Gy per fraction to positive para-aortic lymph nodes.Thirty-seven patients received a positive paraaortic lymph nodes boost or(and) parametrial boost.All patient also received a high-dose-rate intra-cavitary brachytherapy at the point A dose of 20.0-30.0 Gy in 5.0 Gy per fraction.Total chemotherapy cycles were 189,and the average patient received 4.1 courses.Two cases (4％,2/46) experienced grade Ⅲ gastrointestinal toxicities,no patients suffered grade Ⅳ gastrointestinal toxicities.Fifteen cases (33％,15/46) experienced grade Ⅲ hematological toxicities,and 3 (7％,3/46) experienced grade Ⅳ hematological toxicities.Late grade Ⅲ-Ⅳ toxicity was seen in 3 cases (7％,3/46).The 3 year progressionfree survival rate was 46.2％,and the 3 years overall survival rate was 61.2％.Conclusion EF-IMRT and intra-cavitary brachytherapy combined with chemotherapy is safe and effective for stage Ⅰ b1-Ⅳa cervical cancer with positive para-aortic lymph nodes.