Disclosed are a method and apparatus for detecting media data, which relate to the field of conference communications. The method comprises: a detection device receiving media data sent by a first terminal, and then determining, according to first feature information carried in the media data, whether the act of the first terminal sending the media data is legitimate. By means of the method, not only can the identity of a user who discloses media data be determined, media data that is sent illegitimately can also be intercepted in real time, thereby reducing the risk of information leakage.