Embodiments provide a method for transmitting a service stream in a flexible Ethernet and an apparatus. The method includes: obtaining a to-be-transmitted service stream, where the service stream is to be transmitted by using a target virtual connection supported by a physical connection group between a transmit end and a receive end, the physical connection group includes multiple physical connections and supports at least one virtual connection, and the target virtual connection is any one of the at least one virtual connection; determining, from total bandwidth resources of the multiple physical connections and according to timeslot configuration tables used by the multiple physical connections, a timeslot bandwidth resource that belongs to the target virtual connection; and transmitting the service stream to the receive end by using the timeslot bandwidth resource that belongs to the target virtual connection.