In order to meet the performance requirements of long line high speed signal transmission with zero BER, a long distance data transmission system is designed using LVDS interface technology and optical conversion method. Hardware design uses MLH series serial cable equalizer and driver to work together to enhance the coaxial cable differential signal driving capability with adaptive compensation. Extension of the long-line transmission distance by means of combined photoelectric signal transmission. The logic design solves the high-speed data transmission out-of-lock phenomenon by optimizing the judgment flags for valid and invalid numbers. After several high-capacity data reception tests in various experimental environments, it has been demonstrated that LVDS signals can be transmitted without error codes at 300Mbits/s over 100m twisted pair and 2km fiber optic transmission links, and has been put into engineering applications.