The present invention discloses a method for implementing link state passing-through in network, for informing the peer of link fault, said method comprising the following steps: the service device detecting whether there is a link fault in the network; in case of link fault, the service device transferring link fault information to peer service device with a control frame; in response to said control frame containing link fault information, the peer service device disconnecting the user's link and performing corresponding processes; the user at the faulty peer communicating with peer user through the spare network; when said link recovers to normal, the service device at the recovery peer sending a control frame containing link fault recovery information to peer service device to reestablish communication between said users on said link. The present invention is capable of informing the peer of link fault and reducing extra overhead under normal network conditions as much as possible. <IMAGE>