A protection switching method, comprising: receiving, by an intermediate node, a protection switching request message sent by an upstream neighboring node of the intermediate node, wherein the protection switching request message comprises information about a first protection path, the first protection path comprises a first end node, a second end node, and at least one intermediate node, the at least one intermediate node is located between the first end node and the second end node, and the intermediate node is one of the at least one intermediate node; characterized by further comprising: when the intermediate node determines, according to the information about the first protection path, that a protection path resource of the intermediate node is available and that the protection path resource of the intermediate node is idle, sending the protection switching request message to a downstream neighboring node of the intermediate node, and sending a first indication message to the upstream neighboring node of the intermediate node, wherein the first indication message is used to inform the upstream neighboring node of the intermediate node that the protection path resource of the intermediate node is available; and receiving, by the intermediate node, a second indication message that is sent by the downstream neighboring node of the intermediate node according to the protection switching request message, learning, according to the second indication message, that a protection path resource of the downstream neighboring node of the intermediate node is available, and establishing a cross-connection of the first protection path on the intermediate node. receiving, by an intermediate node, a protection switching request message sent by an upstream neighboring node of the intermediate node, wherein the protection switching request message comprises information about a first protection path, the first protection path comprises a first end node, a second end node, and at least one intermediate node, the at least one intermediate node is located between the first end node and the second end node, and the intermediate node is one of the at least one intermediate node; characterized by further comprising: when the intermediate node determines, according to the information about the first protection path, that a protection path resource of the intermediate node is available and that the protection path resource of the intermediate node is idle, sending the protection switching request message to a downstream neighboring node of the intermediate node, and sending a first indication message to the upstream neighboring node of the intermediate node, wherein the first indication message is used to inform the upstream neighboring node of the intermediate node that the protection path resource of the intermediate node is available; and receiving, by the intermediate node, a second indication message that is sent by the downstream neighboring node of the intermediate node according to the protection switching request message, learning, according to the second indication message, that a protection path resource of the downstream neighboring node of the intermediate node is available, and establishing a cross-connection of the first protection path on the intermediate node. when the intermediate node determines, according to the information about the first protection path, that a protection path resource of the intermediate node is available and that the protection path resource of the intermediate node is idle, sending the protection switching request message to a downstream neighboring node of the intermediate node, and sending a first indication message to the upstream neighboring node of the intermediate node, wherein the first indication message is used to inform the upstream neighboring node of the intermediate node that the protection path resource of the intermediate node is available; and receiving, by the intermediate node, a second indication message that is sent by the downstream neighboring node of the intermediate node according to the protection switching request message, learning, according to the second indication message, that a protection path resource of the downstream neighboring node of the intermediate node is available, and establishing a cross-connection of the first protection path on the intermediate node.