The near-bit geosteering drilling technology is a new high-tech .It integrats the techniques of drilling, logging and reservoir engineering. The paper introduced the application of this technology in oil exploration. CGDS is a kind of production of this technology applications. The paper introduced the structure ,function, parameters of CGDS production and its application in oil field. CGDS is recognized as the high and new technique in 21 century which ensures you to achieve the best place of a wellbore within a reservoir by providing geological, engineering parameter measurements and while drilling monitoring. With excellent ability of identification of hydrocarbon reservoir and direction guide, CGDS assists you to adjust and control the wellbore trace in real time according to the information of formation features. Through the introduction of this instrument,We can know more about the near-bit geosteering drilling technology The application prospect and development trend of the geosteering drilling system were also discussed.