The embodiment of the invention discloses a transmission method for multicast message, correlated equipment, and a system. The transmission method comprises the following steps that: an upstream fusion node receives a first protocol independent multicast (PIM) protocol message; according to the first PIM protocol message, a master multicast topology is established; a second PIM protocol message is received; a standby multicast topology is established according to the second PIM protocol message, wherein the second PIM protocol message carries standby multicast identification; the standby multicast topology is configured into a forbidden state; it is determined that there is a fault at the master multicast topology; and after it is determined that there is the fault at the master multicast topology, the standby multicast topology is put into service. According to the invention, the above-mentioned technical scheme can be applied for realization of rapid switching of forwarding paths on the condition that there is a fault, so that normal operation of the service can be ensured.