A data processing method and apparatus are presented, which relate to the communications field and are helpful in improving flexibility and expanding application scenarios. A first physical layer coding data block flow and a second physical layer coding data block flow are received; a first data flow is obtained according to the first physical layer coding data block flow and the second physical layer coding data block flow; multiple subframe headers are generated; a second data flow is obtained according to the first data flow and the multiple subframe headers; and data blocks in the second data flow are distributed 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. The data processing method and apparatus are used for data processing.