Abstract: Objectives  To study the clinical characteristics and early diagnosis of infant with both alpha 1 antitrypin  deficiency (α1-ATD) and biliary atresia (BA). Methods The clinical characteristics, serum biochemical parameters, gene  mutations and treatment of one infant with both α1-ATD and BA was reported. Related literatures about liver disease caused by  α1-ATD were reviewed and analyzed. Results The infant was characterised with neonatal cholestasis, hepatomegaly, elevated  serum ALT, AST, total bilirubin (TB), direct bilirubin (DB) and γ-glutamyltransferase (γ-GT) and absence of bile secretion  from the duodenal drainage tube. BA was confirmed by laparotomy and pathological examination and Kasai′s operation was  performed. Further, the infant was confirmed by SERPINA1 gene mutation analysis, which leads to the diagnosis of α1-ATD. The  case of infant with both alpha 1 ATD and BA has not yet been reported at home and abroad. According to the literatures, children  with α1-ATD were characterized with cholestasis, hepatomegaly, hypoproteinemia, high serum ALT and AST, coagulation  disorders caused by vitamin K1 deficiency and hepatic dysfunction. Prognosis was poor without early diagnosis and treatment.  Conclusions For infant cholestasis, a lot of auxiliary examinations should be performed to identify the etiology of cholestasis.  Gene analysis could help differential diagnosis. Prompt diagnosis and early treatment are the key to improve the survival rate and  prognosis.