By combining the theory of innovation diffusion with mapping knowledge domains, and analyzing diffusion tendency, key nodes and co-occurrence networks of papers on new media published by six journalism and communication journals from 1996 to 2015, this study is to illustrate the diffusion law of ‘new media’ research.This paper reveals that there are two stages in‘ new media’ research in mainland China:‘take-off’ phase and self-sustaining phase. However, it has not yet become an independent and specific branch, and the diffusion of research is obviously dependent on some high-frequency key words. Diffusion outcomes show that digital divide exists between core institutions and ordinary institutions. Journal citation source is expanding from the outstanding journals to the ordinary and journals of other discipline, indicating that ‘new media’ research in mainland China is a closed system on the whole but appears some opening tendency.