A method for transmitting data in flexible Ethernet, FlexE, wherein the method comprises: receiving, by a first FlexE device according to a first client calendar, data that comprises a plurality of data blocks and that is sent by a second FlexE device, wherein the first client calendar indicates a correspondence between a client and a first timeslot set; determining, by the first FlexE device based on an error data block in the plurality of data blocks, that a first timeslot is damaged, wherein the first timeslot corresponds to a damaged processing component in the second FlexE device, the second FlexE device includes a plurality of parallel processing components corresponding to a plurality of timeslots and when one of the plurality of parallel processing components is damaged, an error occurs in a packet that is sent by the second FlexE device in a timeslot corresponding to the damage processing component, wherein the first timeslot set comprises the first timeslot, wherein the determining that a first timeslot is damaged includes performing error checking on an original packet restored from the plurality of data blocks, an error packet in the original packet is determined through the error checking, a data block included in the error packet is an error data block, and one or more timeslots in which the error data block is received are damaged timeslots; adding, by the first FlexE device, a timeslot damage notification to an overhead frame to be sent to the second FlexE device, wherein the timeslot damage notification indicates that the first timeslot is damaged; receiving, by the first FlexE device, a second client calendar sent by the second FlexE device, wherein the second client calendar indicates a correspondence between the client and a second timeslot set, and the second timeslot set comprises a timeslot, other than the first timeslot, in the first timeslot set; and receiving, by the first FlexE device by using the second client calendar, data sent by the second FlexE device. receiving, by a first FlexE device according to a first client calendar, data that comprises a plurality of data blocks and that is sent by a second FlexE device, wherein the first client calendar indicates a correspondence between a client and a first timeslot set; determining, by the first FlexE device based on an error data block in the plurality of data blocks, that a first timeslot is damaged, wherein the first timeslot corresponds to a damaged processing component in the second FlexE device, the second FlexE device includes a plurality of parallel processing components corresponding to a plurality of timeslots and when one of the plurality of parallel processing components is damaged, an error occurs in a packet that is sent by the second FlexE device in a timeslot corresponding to the damage processing component, wherein the first timeslot set comprises the first timeslot, wherein the determining that a first timeslot is damaged includes performing error checking on an original packet restored from the plurality of data blocks, an error packet in the original packet is determined through the error checking, a data block included in the error packet is an error data block, and one or more timeslots in which the error data block is received are damaged timeslots; adding, by the first FlexE device, a timeslot damage notification to an overhead frame to be sent to the second FlexE device, wherein the timeslot damage notification indicates that the first timeslot is damaged; receiving, by the first FlexE device, a second client calendar sent by the second FlexE device, wherein the second client calendar indicates a correspondence between the client and a second timeslot set, and the second timeslot set comprises a timeslot, other than the first timeslot, in the first timeslot set; and receiving, by the first FlexE device by using the second client calendar, data sent by the second FlexE device.