Embodiments of the present disclosure provide a method and a device for establishing a channel, capable of reducing data transmission path length when two WEBRTC terminals transmit data based on an IMS network, reducing network delays, and reducing load of a media gateway device. The method includes: receiving, by a WEBRTC signaling gateway device, a session request message transmitted by a WEBRTC terminal serving as a calling terminal, where the session request message comprises an identifier of a called terminal, determining that the called terminal is a WEBRTC terminal according to the access mode in which the called terminal accesses a WEBRTC signaling terminal, and transmitting the session request message to the called terminal via the WEBRTC signaling gateway device accessed by the called terminal, to enable the calling terminal to establish an end-to-end media channel between the calling terminal and the called terminal according to the session response message.