This application discloses a service data processing method and device. A transmit-end device may generate an optical transport network (OTN) encapsulated signal carrying service data, and generate at least n FlexO (flexible optical transport network) frames based on the OTN encapsulated signal and send the at least n FlexO frames, where r FlexO frames in the at least n FlexO frames carry service check data, and the service check data may be used to restore the service data when bit error rates of k FlexO frames are greater than a reference bit error rate. In this way, if no more than r physical ports included in a FlexO group interface fail, or a bit error rate of no more than r FlexO frames is greater than the reference bit error rate due to another reason, a receive-end device may restore the service data through a received FlexO frame.