The present invention discloses a data transmission method and apparatus. The method comprises: segmenting data to be transmitted into information file segments with a length of Tb bits; performing forward error correction (FEC) coding for Tb information bit sequences composed of bits in same positions in a plurality of continuous information file segments to generate Tb check bit sequences, putting each bit of the check bit sequences in the same position in the check file segments as the corresponding information bit sequences; and transmitting each of the information file segments and check file segments according to their order; the number of bits contained in the information bit sequences being less than or equal to the maximum length of Kmax bits of the FEC-coded information bit sequences.