An embodiment for cancelling echo in online conference systems is provided. According to some embodiments of the present disclosure, the computer-implemented method comprises, in response to an update of devices of participants in an online conference, dividing, by one or more processors, the devices in an online conference into a plurality of groups, wherein the devices located in a same physical location are divided into a same group. The method also comprises, in response to an update of the devices in an online conference, selecting at least one speaker of the devices in each of the plurality of groups as a representative speaker for each of the plurality of groups. The method further comprises forwarding audio data received from microphones of the devices in one of the plurality of groups to the respective representative speaker of other groups of the plurality of groups.