A data transmission method and device are provided. The method includes: a first transmission node sends data signal(s) for first transmission to a second transmission node, wherein the data signal(s) including data of at least one Transmission Block (TB), the TB including K Code Blocks (CBs), and the K CBs being divided into P CB sets; the first transmission node performs packet coding on M CB sets in the P CB sets to obtain S check CB sets; and the first transmission node generates data signal(s) for retransmission and sends the data signal(s) to the second transmission node, the data signal(s) for retransmission at least including Q bits in the check CB sets when a preset condition is met. The embodiments of the present disclosure may effectively reduce resources for retransmission under the condition of not increasing an amount of feedback information.