Objective: The objective of this study is to identify the risk factors for anastomotic complications after one-stage anastomosis for oesophageal atresia.Methods: A retrospective analysis was performed on the clinical data of 107 children with congenital oesophageal atresia who underwent one-stage anastomosis in our hospital from January 2016 to December 2018. Single-factor and multivariate logistic regression analyses were performed to determine the risk factors for anastomotic fistula and anastomotic stenosis.Results: A total of 107 children with oesophageal atresia underwent one-stage anastomosis, and the incidence of anastomotic fistula was 26.2%. The probability of anastomotic stenosis in the long term was 52.3%, and the incidence of refractory stenosis (dilation ≥5 times) was 13.1%. Analysis of the clinical count data in the anastomotic fistula group and non-anastomotic fistula group showed that preoperative albumin (F=4.199, P=0.043), low birth weight (F=7.668, P=0.007) and long gap defects (F=6.107, P=0.015) were risk factors for postoperative anastomotic fistula. Further multivariate logistic regression analysis showed that low birth weight (Wald2=4.499, P =0.034, OR=2.775) and long gap defects (Wald2=6.769, P =0.009, OR=4.939) were independent risk factors for postoperative anastomotic fistula. Premature delivery (F=5.338, P=0.023), anastomotic fistula (F=11.381, P=0.001), endoscopic surgery (F=6.343, P=0.013), preoperative neutrophil count (F=8.602, P=0.004), preoperative low albumin (F=8.410, P=0.005), and a preoperative prognostic nutritional index < 54 (F=5.54, P=0.02) were risk factors for long-term anastomotic stenosis in children. Further multivariate logistic regression analysis showed that postoperative anastomotic fistula (Wald2=11.417, P =0.001, OR=8.798), endoscopic surgery (Wald2=9.633, P =0.002, OR=4.808), and a prognostic nutritional index < 54 (Wald2=4.540, P =0.002, OR=2.3798) were independent risk factors for long-term anastomotic stenosis.Conclusion: Low birth weight and long gap defects are important predictors of postoperative anastomotic fistula, and the possibility of long-term anastomotic stenosis should be considered. The long-term risk of anastomotic stenosis was increased in children undergoing endoscopic surgery and in those with a preoperative prognostic nutritional index < 54.