Objective@#To evaluate the effect of preservation of left colic artery (LCA) on postoperative anastomotic leakage in patients with rectal cancer after neoadjuvant therapy.@*Methods@#A retrospective cohort study was conducted to collect data of rectal cancer patients at Department of Gastrointestinal Surgery of Fujian Cancer Hospital from September 2014 to August 2017. Inclusion criteria: (1) age of 18 to 79 years; (2) rectal adenocarcinoma confirmed by postoperative pathology; (3) patients without preoperative serious cardiovascular and cerebrovascular disease receiving preoperative neoadjuvant radiotherapy or chemoradiotherapy; (4) laparoscopic-assisted anterior rectal resection and distal ileostomy were performed simultaneously; (5) complete clinical data. Exclusion criteria: patients with extensive abdominal metastasis, or distant organ metastasis during operation, and combined organ resection. According to whether LCA was retained during operation, the patients were divided into two groups, then the intraoperative and postoperative clinical outcomes were compared. Moreover, univariate analysis and multivariate logistic regression were used to analyze risk factors of postoperative anastomotic leakage.@*Results@#A total of 125 patients were included in this study, including 56 patients in the retained LCA group and 69 patients in the non-retained LCA group. Differences in baseline data, such as gender, age, diabetes mellitus, body mass index, hemoglobin, distance between tumor and anal margin, maximum diameter of tumor, preoperative neoadjuvant therapy, and ypTNM stage, between retained LCA group and non-retained LCA group were not statistically significant (all P>0.05), indicating that two groups were comparable. Meanwhile there were no significant differences in operation time, intraoperative blood loss, total number of lymph node harvested, number of harvested lymph node at the root of inferior mesenteric artery, circumferential margin, anastomotic bleeding, or postoperative hospital stay between two groups (all P>0.05). Thirteen patients in the non-retained LCA group (18.8%) developed postoperative anastomotic leakage, including 7 cases of grade A, 5 cases of grade B and 1 case of grade C, while in the retained LCA group, only 5.4% (3/56) of patients developed postoperative anastomotic leakage, including 1 case of grade A and 2 cases of grade B without case of grade C, whose difference was statistically significant (U=1674.500, P=0.028). Univariate analysis showed that preoperative hemoglobin <120 g/L and non-retained LCA were associated with postoperative anastomotic leakage (both P<0.05). Multivariate analysis cofirmed that preoperative hemoglobin < 120 g/L (OR=3.508, 95% CI: 1.158 to 10.628, P=0.017) and non-retained LCA (OR=4.065, 95%CI: 1.074 to 15.388, P=0.031) were independent risk factors for postoperative anastomotic leakage. Median follow-up time was 31 months (16 to 51 months), and no long-term complication was found. Local recurrence and distant metastasis were found in 1 case (1.8%) and 7 case (12.5%) in the retained LCA group, while those were found in 2 cases (2.9%) and 5 cases (7.2%) respectively, in the non-retained LCA group, whose differences were not statistically significant (P=1.000, P=0.321 respectively).@*Conclusion@#Preservation of left colic artery not only can ensure radical lymph node dissection efficacy under the condition of similar operation time and blood loss, but also can effectively reduce the incidence of postoperative anastomotic leakage for rectal cancer patients after neoadjuvant therapy.