A method and device for transmitting a control message based on a multi-ring Ethernet are provided, wherein the method comprises the following steps: control virtual local area networks of a main ring and a sub-ring are configured (S1002); and a main ring node receives a sub-ring control message from the sub-ring, forwards the sub-ring control massage to the other main ring nodes on the main ring via a data plane, and synchronously realizes the blocking or opening of the sub-ring control message and a data message in the data plane (S1004). With the technical scheme of the present invention, the sub-ring control message is forwarded by the main ring node via the data plane, which avoids the latency of a sub-ring control message processing performed by a control plane, and thus solves the problem that the time for the main ring node to process the sub-ring control message is too long during existing control message transmission process, avoids the control message loop situation caused by the transmission of the sub-ring control message over the main ring, and improves the network performance.