This application discloses a client service transmission method and apparatus. The method may include: receiving a client service, where the client service includes a plurality of data blocks, the client service is corresponding to a counter, and the counter is used to control an output rate of the client service; and sending the plurality of data blocks in a plurality of sending periods, where when a count value of the counter reaches a preset threshold in each sending period, at least one data block of the plurality of data blocks is sent. This technology may be applied to a scenario in which a transmission node transmits a client service.