To explore the preoperative nutrition status in patients with biliary atresia (BA) and its effect on the cholangitis of Kasai portoenterostomy (KPE). 106 patients who had been diagnosed with BA type III and were undergoing KPE were divided into two groups according to the score obtained using STRONGkids. Preoperative and postoperative data were collected to compare general characteristics and postoperative outcomes between the different groups. Forty-nine (46.2%) patients were at moderate nutritional risk (MNR) and fifty-seven (53.8%) patients were at high nutritional risk (HNR) preoperatively. The MNR group had shorter postoperative hospitalization times than the HNR group (P = 0.023). The initial postoperative cholangitis occurred later (P = 0.002) and the incidence of early cholangitis was lower (P = 0.029) in patients at MNR than in those at HNR. The ratio of jaundice clearance (P = 0.02) and 2-year native liver survival (P = 0.0109) were significantly higher in MNR group than in HNR group. Patients with BA presented the greatest nutritional deficiencies and patients at HNR are more vulnerable to the early cholangitis and the rate of jaundice clearance is lower than those at MNR. The occurrence of initial postoperative cholangitis in MNR group was later than in HNR group.