A data transmission device includes a data division unit for receiving an original transmission data and dividing the original transmission data into a plurality of division data; a data generation unit for generating a plurality of packet data according to the plurality of division data and a plurality of clock data, wherein each of the clock data is a multi-bit data; and a data output unit for outputting the plurality of packet data to a data reception device; where each of the packet data includes a division data and a clock data, each of the packet data corresponds to a packet data period, and the division data corresponds to a division data period of the packet data period and the clock data corresponds to a clock period of the packet data period.