In the multiple contexts such as the transformation of modernity, the intensification of globalization, and the Internet revolution, public communication is on the stage as a research paradigm and a practical solution. This paper defines public communication as a process, activity, and phenomenon of public consultation based on publicity among multiple subjects, aiming at promoting social identity and public good. Having returned to the original genealogy of knowledge and social context, this paper confirms following elements of public communications: the subject-multiple subjects, ethical norm and practical principle-mutual subjectivity and publicity, field-public sphere as opinion exchange platform, action space, and network of significance, means-discourse/dialogue/conversation, goal and effect-identification, consensus, and recognition. Finally, this paper proposes that we should return to human existence, life world, and community to facilitate the transformation of public communication and communication research paradigm.