The present invention discloses an image controlling method, device, and system for a composed-image video conference, where the method includes receiving audio data of sites; obtaining, according to audio data of each site of the sites and in real time, a voice feature value that is within a first specified period and of a corresponding site, where the voice feature value is used to represent an activation state of the site; selecting a specified site from the multiple sites according to an activation state of each site; and filling a picture of the specified site into a sub-image of a composed image, to update the composed image in real time. This remarkably improves an effect of a conference, and improves experience of participants. In addition, a quantity and locations of sub-images in the composed image may be further adjusted dynamically, which also effectively improves the effect of the conference.