A link protection method in a software-defined networking (SDN), a corresponding switching device and network controller, where the method includes receiving, by a first switching device in the SDN, first information from a network controller in the SDN and link protection information, where the first information establishes a communication link between the first switching device and a destination device, and the link protection information instructs the first switching device to proactively perform primary-to-secondary link switching when a link is faulty, establishing, by the first switching device, the communication link with the destination device according to the first information, and determining, by the first switching device according to the link protection information, that the first switching device proactively performs the primary-to-secondary link switching.