Abstract: The present disclosure provides a method, switch and system for updating a route, relating to computer network technologies. The method comprises detecting, by a current device, link states of at least two neighbor devices; when the current device detects that a link state of a first neighbor device is unreachable, setting, by the current device, a state of a routing item with an initial state being reachable among all routing items corresponding to the first neighbor device in an internal routing table to be unreachable; and detecting, by the current device, whether states of all routing items corresponding to each target subnet in the internal routing table are all unreachable, respectively; if yes, sending a route updating message to another neighbor device except the first neighbor device.