The invention discloses a method, a device and a system for broadcasting messages in a vehicular ad-hoc network (VANET), relating to the technical field of communication, and invented for solving the problem that a success rate of receiving event-driven safety messages (ESM) is low in VANET. The method provided by the invention comprises the steps: a source node adds a forwarding identifier which instructs a neighbor node to forward the ESM into the ESM, when the ESM is generated within the time interval of a control channel (CCH); the source node broadcasts the ESM added with the forwarding identifier to the neighbor node via the CCH; the neighbor node finds whether the ESM carries the forwarding identifier; and if the forwarding identifier is found, the neighbor node broadcasts the ESM to own neighbor node via a service channel (SCH) after being switched to the SCH. The method, the device and the system provided by the invention are mainly applied to a message broadcasting process between vehicles under a road traffic environment.