Objective To explore the occurrence status of infection after Kasai procedure (KP) in children with biliary atresia and its risk factors. Methods A retrospective study was performed to analyze the clinical data of 397 children with biliary atresia receiving KP, and children were assigned to non⁃infection group (159 cases) or infection group (238 cases) according to the presence of infection occurrence after surgery. The subgroup analysis was performed on the infection group, and relevant clinical data were compared between the non⁃infection group and the infection group. The multivariate Logistic regression model was adopted to analyze the risk factors for children with biliary atresia suffering from infection after KP. Results The incidence rate of infection among 397 children with biliary atresia after KP was 59.9% (238/397), and the incidence rate of cholangitis was 57.2% (227/397). The preoperative body weight and gamma⁃glutamyl transpeptidase of the infection group was higher than those of the non⁃infection group, and the preoperative serum total bile acid level, preoperative body weight, and preoperative height of the early infection group were higher than those of the late infection group (P<0.05). The multivariate Logistic regression analysis revealed that high preoperative body weight, high preoperative total bilirubin, and low preoperative AST level were the risk factors for the occurrence of infection in children with biliary atresia after KP (P<0.05). Conclusion High preoperative body weight, high preoperative total bilirubin and low preoperative AST level are the risk factors for the occurrence of infection in children with biliary atresia after KP.