The present document discloses a link keep-live method, a controller and a switch, including: acquiring link information by the controller, after the link information is acquired, sending the link information to a source switch and/or destination switch of a link corresponding to the link information; and, correspondingly sending keep-live mode information and a link keep-live starting instruction to the source switch and/or destination switch, triggering the source switch and/or destination switch to perform the link keep-live between the source switch and destination switch according to the link information and keep-live mode information; or, after the controller acquires the link information, sending the link information to the source switch and/or destination switch of the link corresponding to the link information, triggering the source switch and/or destination switch to determine a mode adopted for link keep-live, performing the link keep-live between the source switch and destination switch according to the determined mode.