This application provides a method and device for transparently transmitting a service frequency, where the method includes: determining, by a first device, first service frequency information Xn, where the first service frequency information Xn is used to indicate an amount of n-bit first service data that is sent by the first device within first statistical duration, and a sending frequency of the first device is used as a reference for the first statistical duration; and encapsulating, by the first device, the first service frequency information Xn into a first S/T bit code block, inserting the first S/T bit code block into a data stream of the first service data, and sending the data stream of the first service data to a second device.