The invention embodiments relate to wireless communication field, and disclose a data sending control method and a data transmission device. The invention involves receiving data from a sender for storing in the buffer, and forwarding the buffered data to the receiver; receiving ACK that represents having received data returned from the receiver; adding or deleting ACK returned from the receiver according to the volume of data unsent in the buffer, sending the processed ACK to the sender, through the processed ACK controlling the sending rate of the sender, and making the transmission of data reliable and highly efficient.