Health preservation is a humble defense against the fear and anxiety of death. According to the theory of fear management, individuals mainly cope with the death anxiety caused by the consciousness of death through three defense mechanisms: world outlook, self-esteem and affinity. The mainstream view is that the three defense mechanisms are equal in defending death anxiety and conform to the mobile compensation mechanism. This paper discusses the limitations of the mobile compensation mechanism, and puts forward a new viewpoint on the relationship between the three defense mechanisms: the priority hypothesis, which holds that the three defense mechanisms are not equal, but have priority: intimacy takes precedence over world outlook and self-esteem, and world outlook takes precedence over self-esteem. After sorting out the supporting evidence, this paper tries to put forward a possible explanation of the priority hypothesis from the perspective of development, and thinks that this priority comes from the development order and derivative relationship of the defense mechanism.