The patients were divided into two arms according to the defined conditions (pathology rectal adenocarcinoma；distal distance of tumor from anal verge < 10cm；TNM staging T3-4N0-2；no distant metastasis；Karnofsky score≥70) in this prospective, single center, open, non randomized trail (arm A:concurrent chemoradiotherapy, arm B:sequential therapy). Regimens:Arm A:50Gy,2Gy/day per time, 5 days a week, for 5 weeks. +capecitabine 850mg/m2 bid on the day accept radiotherapy. Rest for 8 weeks. Arm B: XELOX 2 cycles (oxaliplatin 130mg/m2 ivgtt 2-6h day 1, capecitabine 1000 mg/m2 Bid day 1-14, repeat every 3 weeks ) → 50Gy,2Gy/day per time, 5 days a week, for 5 weeks.+capecitabine 850mg/m2 bid on the day accept radiotherapy → XELOX 1 cycle. Rest for 2 weeks. Evaluate pre chemotherapy, pre radiotherapy and pre surgery individually. Surgeries followed TME(total mesorectal excision) and PANP(pelvic autonomic nerve preservation) for patients in both arms. Take pathological evaluation of tumors. Take XELOX therapy till 6-8 cycles(pre and after surgery total). Follow up according the schedule.