A method for transmitting a data stream in a flexible Ethernet, comprising: Obtaining a to-be-transmitted data stream, wherein the data stream is to be transmitted by using a physical connection group between a transmit end and a receive end, and the physical connection group comprises N physical connections; Allocating the data stream to the N physical connections according to a sequence of the N physical connections in the physical connection group, so as to obtain N sub-streams respectively corresponding to the N physical connections; and Transmitting the N sub-streams by using the N physical connections, wherein a sub-stream transmitted over each physical connection comprises configuration status information of each physical connection, the configuration status information comprises an identifier of each physical connection and an identifier of a physical connection that is adjacent to each physical connection and that is in the physical connection group, and configuration status information of the N physical connections jointly indicates the sequence of the N physical connections; characterized in that the configuration status information of each physical connection further comprises first indication information and/or second indication information, the first indication information is used to indicate whether a current physical connection is a first physical connection in the physical connection group, and the second indication information is used to indicate whether a current physical connection is a last physical connection in the physical connection group, wherein the sub-stream transmitted over each physical connection further comprises third indication information, and the method further comprises: when a quantity of physical connections in the physical connection group and/or the sequence of the physical connections in the physical connection group change or changes, negotiating, by using the third indication information, with the receive end to update the physical connection group. Obtaining a to-be-transmitted data stream, wherein the data stream is to be transmitted by using a physical connection group between a transmit end and a receive end, and the physical connection group comprises N physical connections; Allocating the data stream to the N physical connections according to a sequence of the N physical connections in the physical connection group, so as to obtain N sub-streams respectively corresponding to the N physical connections; and Transmitting the N sub-streams by using the N physical connections, wherein a sub-stream transmitted over each physical connection comprises configuration status information of each physical connection, the configuration status information comprises an identifier of each physical connection and an identifier of a physical connection that is adjacent to each physical connection and that is in the physical connection group, and configuration status information of the N physical connections jointly indicates the sequence of the N physical connections; characterized in that the configuration status information of each physical connection further comprises first indication information and/or second indication information, the first indication information is used to indicate whether a current physical connection is a first physical connection in the physical connection group, and the second indication information is used to indicate whether a current physical connection is a last physical connection in the physical connection group, wherein the sub-stream transmitted over each physical connection further comprises third indication information, and the method further comprises: when a quantity of physical connections in the physical connection group and/or the sequence of the physical connections in the physical connection group change or changes, negotiating, by using the third indication information, with the receive end to update the physical connection group.