Objective To investigate the risk factors of anastomotic leakage after transanal total mesorectal excision.Methods Retrospective analysis of clinical data of 46 patients with rectal cancer who underwent TaTME surgery from May 2015 to May 2018 in Daping Hospital,Army Medical University.There were 22 males and 24 females,the median age was 61.2 (range from 40 to 79)years.To observe the correlation between perioperative factors and anastomotic leakage,including preoperative staging,operation time,bleeding volume,anastomotic approach,anastomotic height,intraoperative adverse events,and concurrent diseases.The software of SPSS 20.0 was adopted to analyze the above indicators.Results Among 46 patients with rectal cancer,38 were treated with TaTME combined with laparoscopic surgery,5 with robotic transanal combined with transabdominal surgery,and 3 with pure transanal total mesorectal excision.There were no deaths in the whole group.The incidence of postoperative anastomotic leakage was 13.0％,1 case of grade B and 1 cases of grade A anastomotic leakage,both accounting for 2.2％ and 4 cases of grade C anastomotic leakage,accounting for 8.7％.Anastomotic leak discovery time average (9.8 ± 4.8) d.No anastomotic leakage occurred in 17 cases of ileostomy.Among them,diabetes mellitus,protective ostomy,blood loss ≥ 100 ml,BMI,height of anastomosis and total operation time were significantly correlated with anastomotic leakage.Conclusions In addition to the influence of the learning curve during TaTME surgery,obesity,diabetes,anastomotic height,intraoperative blood loss ≥ 100 ml,and prolonged total operation time are risk factors for anastomotic leakage.Ileal protective ostomy is valuable for reducing anastomotic leakage.