The invention provides a locator/identity separation protocol host migration method and a locator/identity separation protocol host migration device. The locator/identity separation protocol host migration method comprises the steps that: a TR receives a mapping request message sent by an MS, wherein the mapping request message carries a RLOC of a far-end TR and an EID of a host; the TR places the RLOC of the far-end TR into a local far-end TR list; the TR receives a mapping notification message sent by the MS or other TR, wherein the mapping notification message carries a mapping relation of EIDs and RLOCs; one RLOC corresponding to the EID carried by the mapping notification message is looked up in the recorded mapping relation of the EIDs and the RLOCs; and whether the found RLOC is consistent with the RLOC carried by the mapping notification message is compared, if not, SMR messages are sent to the far-end TR corresponding to each RLOC in the far-end TR list, wherein the SMR messages carry the EID in the mapping notification message. The locator/identity separation protocol host migration method and the locator/identity separation protocol host migration device accelerate the flow migration speed during host migration.