Abstract: The center cable-type drilling rod for coal mine can not only transmit electric power signals from orifice to downhole, but also establish a two-way high-speed information channel between devices of orifice and downhole. This paper introduces the design of outer pipe and inner structure of the cable-type drilling rod and researches critical factors influencing signal transmission. This key technology can ensure the stability and reliability of final signal transmission and ensure safe and highly efficient mining only when is given full attention.