Abstract: This paper studies TV public domain and TV interacting behavior with TV information as medium.The study shows that TV public domain consists of TV public，TV information exchange field and TV interacting behavior with TV information as medium.The author points out that TV public is characteristic of social connection，reflection and interacting through information exchange.Interacting behavior centering on TV information exchange is rationalized when carried out with authenticity，correctness，sincerity and intelligibility.Thus，an ideal TV information exchange domain can be achieved when rationalization is taken as standardized requirements in the interaction among the objective world，the social world and the subjective world.

Key words: TV public, public domain, interacting field, interacting behavior, rationalization