The present invention provides a service triggering method, device and system, and a media server. The method comprises: creating a media channel for a playback service, a media channel for a speech recognition service and a media channel for a signal reception service; receiving a trigger signal for trigging a service when a prompt tone is played through the media channel for a playback service; acquiring information contained in the trigger signal through the media channel for a signal reception service or the media channel for a speech recognition service; and reporting the acquired information contained in the trigger signal to an application server. The present invention solves the problem of passive selection of one trigger service of a signal reception mode and a speech recognition mode in the related art, and realizes the effect of actively selecting, according to an input trigger signal, the signal reception mode or the speech recognition mode to trigger a service.