Abstract： Objective:To examine the prognosis factors for non-reversal of defunctioning ileostomy in rectal cancer surgery.Methods:The data of 234 patients with rectal cancer undergoing radical resection and defunctioning ileostomy in the Department of General Surgery, Beijing Friendship Hospital, Capital Medical University from January 2013 to June 2020 was analyzed retrospectively. There were 166 males and 68 females, aging ( M(IQR)) 62(12) years (range: 33 to 89 years). Telephone following-up was conducted intensively in July 2021 to investigate whether stoma was reversed, causes of reversal failure, and tumor recurrence or metastasis after surgery. The non-reversal stoma was defined as stoma not being reversed during the follow-up period (more than 12 months). The χ 2 test or Fisher′s exact test was used to conduct a univariate analysis of clinical data related to reversal failure, and the factors with P<0.05 were selected into Logistic regression for multivariate analysis. Results:A total of 165 patients received stoma reversal postoperatively with an interval time of (6.5±2.4) months (range: 0.9 to 17.8 months), but 69 patients failed to closure of stoma. Univariate analysis showed that age, concomitant diseases, surgical methods, preoperative hemoglobin, preoperative carcinoembryonic antigen, tumor maximum diameter, depth of invasion, lymph node metastasis, TNM stage, anastomotic-related complications, postoperative tumor local recurrence or distant metastasis were associated with non-reversal of diverting ileostomy in rectal cancer surgery (all P<0.05). Multivariate analysis showed that age ( OR=2.270, 95% CI: 1.150 to 4.479, P=0.018), open surgery ( OR=7.249, 95% CI: 1.977 to 26.587, P=0.003), preoperative hemoglobin<120 g/L ( OR=3.092, 95% CI: 1.566 to 6.105, P<0.01), anastomotic-related complications ( OR=4.375, 95% CI: 1.686 to 11.349, P=0.002), postoperative local recurrence or distant metastasis ( OR=7.065, 95% CI: 2.591 to 19.264, P<0.01) were independent prognosis factors for reversal failure of defunctioning stoma in rectal cancer surgery. Conclusions:There is a high risk of reversal failure of defunctioning ileostomy among rectal cancer patients with age>65 years, open surgery, preoperative hemoglobin<120 g/L, anastomotic-related complications, postoperative local recurrence or distant metastasis. Colorectal surgeons should fully evaluate the outcome and risk of reversal failure before making a decision of diverting ileostomy. Reducing anastomotic complications is helpful to the successful return of preventive ileostomy.