This qualitative research used documentary data to content analysis Dhamma lecture of Buddhadasa Phikkhu that printed and widely published. Research objective is to analyze Buddhadasa Phikkhu's philosophy and studied his concepts and theory of communication. The result can be concluded that reality in Buddhadasa Phikkhu's opinion has 2 level (1) Truth (Ultimate Reality) is "Dhamma": the universal reality; the emptiness (2) Supposed Reality (Constructed Reality) is the reality we communicate in everyday life. Communication is the relativity system of human that can divide by 2 level of reality. (1) Communication of "human & nature" and "human & themselves". To use "Dhamma language" may point approximately to meaning of truth. In this level, human acts receiver role to reach personal goal: to maintain balance in interrelation system within each of them. There is not goodness and beauty in this level. (2) Communication of "human & human" and "human & social". In this level, human uses "Human language" to sharemeaning of supposed reality, for reach ethics goal: world peace. Goodness is to be communicating to dissolve selfish. Beauty is passage to goodness by persist human in it's charisma so that them forget egoism for moment. Human play both receiver and sender role in social, especially good sender role. For example, to use verbal message (verbal behavior) that give the benefits of people and not injury to truth, beauty and brotherhood. Buddhadasa Phikkhu's way of communicate to public is in this level. He use varieties of media such as human, nature, print, electronics and miscellaneous media. Buddhadase Phikkhu has theory of knowledge in his own way nearly to empiricism. He accepts not only data from five sensations channel but also throught and feeling from "mind" channel. He said that experience from mind channel is empirical data and so important to human's relation with themselves and the world outside. The value of his knowledge can be judged buy the way of utilitarianism and pragmatism. Knowledge must be fulfilling its duty to give the benefits for all people and to be the method to practice. He also belief in human ability to reach them highest spiritual level, so we can conclude that he is humanism. At last, communication should reveal the real world to human, make them realize the truth, Dhumma, nirvana and freedom within themselves.
