Inclusion Criteria:  Type III biliary atresia hepatojejunostomy； Gestational age at birth ≥ 36 weeks； Infants aged 0-3months； Weight ≥ 2kg when entering the group； Informed consent of family members  Exclusion Criteria:  There are known immune deficiencies； Severe surgical complications (such as intestinal obstruction, massive bleeding, etc.) -occurred during or within 72 hours after the operation； The child's mother has human immunodeficiency disease, or HBsAg positive, or HCV positive； Complicated with other systemic serious diseases (such as congenital multiple malformations, chromosome abnormalities)