A protection switching method, including sending, by a first end node, a first protection switching request message to an intermediate node in response to a fault occurring on a working trail between the first end node and a second end node, wherein a protection trail of the working trail comprises the first end node, the second end node, and at least one intermediate node, receiving, by the first end node, a second protection switching request message from the intermediate node, and switching service data to the protection trail for transmission in response to receiving the second protection switching request message, where one overhead frame of each of the first and second protection switching request messages has at least two overhead information groups, and each of the at least two overhead information groups comprises a request type field, a request signal identifier field, and a bridge flag field.