In the current mediated society,all people expect the mass media should be morally accountable .It's out of question of the rightness of the expectation . Though,at the time when the obligation of the mass mediais emphasized,we should beawareof how thecurrent status has come into being,and whoor which should be accountability .We must learn about the following . Firstly,the basic function of mass media is information and public supervision .Secondly,the essence of the trivalization of the mass media is that the mass media is catering for the mass . That's to say,it's the mass's trivalization that makes the mass media trival .Finally,the deletion and weakness of relative basic theory in media ethics should be accountable,too . As we know,this kind of deletion and weakness would conduce inability of guidance upon correlative act.