A data processing method, comprising: Receiving a first physical layer coding data block flow and a second physical layer coding data block flow; obtaining a first data flow according to the first physical layer coding data block flow and the second physical layer coding data block flow, wherein the first data flow comprises data blocks from the first physical layer coding data block flow and data blocks from the second physical layer coding data block flow, and a ratio of a rate of the data blocks that are from the first physical layer coding data block flow and are in the first data flow to a rate of the data blocks that are from the second physical layer coding data block flow and are in the first data flow is equal to a ratio of a rate of the first physical layer coding data block flow to a rate of the second physical layer coding data block flow; generating multiple subframe headers, wherein the multiple subframe headers are obtained according to a frame header, the frame header comprises multiple payload fields, and the multiple subframe headers comprise the multiple payload fields, wherein each subframe header comprises only one payload field and a subframe header marker field used to indicate whether the only one payload field is the first subframe header in the multiple subframe headers, each subframe header is one or more data blocks, the multiple subframe headers further comprise multiple beginning flag fields, and each subframe header comprises only one beginning flag field, wherein the only one beginning flag field is used to indicate a start of a subframe header in which the only one beginning flag field is located, and the only one beginning flag field is a data block; obtaining a second data flow according to the first data flow and the multiple subframe headers, wherein the second data flow comprises the first data flow and the multiple subframe headers; and distributing data blocks in the second data flow to a first physical medium dependent PMD sublayer circuit and to a second PMD sublayer circuit, so as to obtain a first PMD sublayer data flow and a second PMD sublayer data flow, wherein the first PMD sublayer circuit corresponds to the first PMD sublayer data flow, and the second PMD sublayer circuit corresponds to the second PMD sublayer data flow. Receiving a first physical layer coding data block flow and a second physical layer coding data block flow; obtaining a first data flow according to the first physical layer coding data block flow and the second physical layer coding data block flow, wherein the first data flow comprises data blocks from the first physical layer coding data block flow and data blocks from the second physical layer coding data block flow, and a ratio of a rate of the data blocks that are from the first physical layer coding data block flow and are in the first data flow to a rate of the data blocks that are from the second physical layer coding data block flow and are in the first data flow is equal to a ratio of a rate of the first physical layer coding data block flow to a rate of the second physical layer coding data block flow; generating multiple subframe headers, wherein the multiple subframe headers are obtained according to a frame header, the frame header comprises multiple payload fields, and the multiple subframe headers comprise the multiple payload fields, wherein each subframe header comprises only one payload field and a subframe header marker field used to indicate whether the only one payload field is the first subframe header in the multiple subframe headers, each subframe header is one or more data blocks, the multiple subframe headers further comprise multiple beginning flag fields, and each subframe header comprises only one beginning flag field, wherein the only one beginning flag field is used to indicate a start of a subframe header in which the only one beginning flag field is located, and the only one beginning flag field is a data block; obtaining a second data flow according to the first data flow and the multiple subframe headers, wherein the second data flow comprises the first data flow and the multiple subframe headers; and distributing data blocks in the second data flow to a first physical medium dependent PMD sublayer circuit and to a second PMD sublayer circuit, so as to obtain a first PMD sublayer data flow and a second PMD sublayer data flow, wherein the first PMD sublayer circuit corresponds to the first PMD sublayer data flow, and the second PMD sublayer circuit corresponds to the second PMD sublayer data flow.