Establish design assurance system is the most direct embodiment of implmenting airworthiness requirements.Chinese aviation industries are mainly dedicated on military aircraft，lack of experience in civil aviation research and development，lack of understanding of how to establish design assurance system and implement design assurance system.This paper describs airworthiness management mode at home and abroad ,design assurance system requirments and the necessity of establishing design assurance system. This paper expounds the contents of learning comprehension,comparative analysis,document implementation and continuous improvement，and puts forward the methods and ideas of establishing design assurance system。