With the development of the mediatizaiton in current society, the legitimacy of media sociology began to emerge. In response to Li Hongtao and Huang Shunming's research on the boundary work of Media sociology of Britain and America, this paper holds that the first step in exploring the boundary problem of media sociology is to clarify the meaning of “media” and “society”. However, Li Hongtao and Huang Shunming did not reach a unified understanding on “media” and “society”, which directly led to the failure of their boundary work. The “Media turn” of Birmingham cultural studies promoted the development of media theory. Media has gradually been liberated from the shackles of traditional information dissemination and acquired the subjective status of equal dialogue with the society, thus contribute to the rising of media sociology. Current media practice has further promoted the discussion of mediatization. Media not only regulate society, but also construct the existence of the society. Only in this way can the valuable media sociology theory come into being.