Abstract: Responsibility ethics is the essence and core category of public health ethics.Role responsibility consciousness,overall responsibility thinking and moral self-discipline are not only the basic elements and essential characteristics of responsibility ethics,but also the meaning and important attributes of public health ethics.The subjects of public health moral responsibility include public health professionals and all relevant persons inside and outside public health activities such as the government,media,enterprises and individual citizens.The former bears the professional responsibility of public health,while the latter shares the common responsibility with public health professionals.The content of public health moral responsibility includes retrospective responsibility and forward-looking responsibility,the former is to investigate the negligence of public health subjects,and the latter is a preventive responsibility for the risk of public health activities and oriented to future behavior.The limit of moral responsibility of public health shows a trend of extending from "limited liability" to "unlimited liability",the former being the role responsibility of the subject in public health activities,while the latter being the universal social responsibility responsible for the whole society and human health.

Key words: public health, ethics of responsibility, subject, nature, limit