A method and an apparatus for processing link state information is provided. A first network device receives first link state information sent by a second network device, where the first link state information is link state information of a third network device; in response to receiving the first link state information, the first network device deletes second link state information that is received by the first network device from the second network device, where the second link state information carries a segment identifier of the third network device; and the first network device deletes, based on the first link state information, third link state information received from the second network device, where the third link state information carries information for computing a route to the third network device.