By analyzing the scope of appellate review in the draft reform of the appellate mechanism in bilater-al treaties,the EU investment court system and the third Working Group of the United Nations Commission on In-ternational Trade Law,this paper points out that the existing scope of appellate review has broad scope of appellate review,vague standards and unclear relationship between the appellate procedure and the revocation procedure,and it can be resolved by clarifying the power of the appellate mechanism.Finally,based on China's national condi-tions,this paper proposes the attitude in the reform of the ISDS appeal mechanism and includes the provisions of the appeal mechanism in the signing of the bilateral investment treaty,which may lay the foundation for the subse-quent reform.