<p>A method and device for transmitting data, select and transmit the data message which is waiting for acknowledgement initiatively when needn't to transmit the retransmission or new data message at the sending end currently. The present invention retransmits data initiatively by use of the idle bandwidth, thus can improve the transmission success ratio of the data message, and improve the utilization ratio of channel resource; and then achieve the purpose of reducing the delay through the time diversity gain acquired by carrying out retransmission of data message initiatively through idle bandwidth.</p>
