Abstract: In the field of organ donation and transplantation, the determination of death faces the dilemma of the separation between medical standards and social cognition, which may hinder medical practice and lead to controversial legal evaluations. Establishing brain death criteria through the "hard law" model is the path currently adopted by many countries. However, this approach has limitations, such as the attribution of the right to define death in the law, the conflict between the technological iteration of brain death criteria and legal stability, and the neglect of the social construction of the concept of death. Based on the theory of gradual social engineering and social systems theory, establishing brain death criteria through the "soft law" model has both scientific adaptability and governance flexibility, and is conducive to cultivating social consensus on brain death criteria. In terms of implementation, it is essential to focus on the high-level positioning of the "soft law" formulation entities for brain death criteria, the professionalization of the implementation entities, the publicization of the formulation process, and the institutionalization of risk communication strategies. At the same time, it is necessary to strengthen the informed consent of close relatives and design a dispute resolution mechanism for misjudgments of brain death to guard against potential improper risks.