The application of mandatory rules is one of the most common and complicated issues in international commercial arbitration.This stems from the tense relationship between the principle of party autonomy,the state's public power reflected in mandatory rules,and the arbitrator's obligation to balance the two to make enforceable awards.In the theory and practice of international arbitration,there is still a lack of unified practice and theoretical consensus on how the arbitral tribunal should apply mandatory rules.However,mandatory rules generally exist in the law applicable to the contract,the law applicable at the seat of the arbitration,and the law of the third country,which can directly threaten the effectiveness of arbitration and must be paid attention to.The law in China lacks detailed rules on the application of substantive arbitration laws,and there are significant differences in the application of mandatory rules among arbitration institutions.The inadequacy of certainty and predictability in the rules of application of law is not conducive to parties in the selection of Chinese arbitration,and is also inconsistent with the China's overall requirements to develop international arbitration.It is suggested to start from the attributes of international commercial arbitration,refer to the practice and theory of international arbitration,and not directly reflect the content of mandatory rules in the Arbitration Law and arbitration rules.Instead,the application of mandatory rules should be determined by the arbitration tribunal within its discretion.