This dissertation is based on the broad collection, deep investigation and research of the policy and regulation of design assurance of international main airworthiness authorities and the implementation status of design assurance systems of main aircraft manufacturers. It illustrates a comprehensive analysis with scope from the design assurance origin, background, current policy requirements of airworthiness authorities from four main influential airworthiness authorities including EASA, TCCA, FAA and CAAC, to the interaction relationship with industry manufacturers, as well as the future development trends for the design assurance system. It brings a beneficial reference for Chinese airworthiness authority and aerospace industry manufacturers developing related design assurance policy, developing and review design assurance system, and carrying out international certification policy coordination.