Abstract: In order to solve the problems of underground directional drilling technology and equipment which is unable to recognition stratum and has low drilling ef ficiency and coal drilling meeting efficiency, based on the recognition stratum of coal formation strata natural gamma, natural gamma measurement technology, signal W ire transmission technology and signal demodulation technology are studied, and the mine cable geosteering MWD device and geological directional drilling technology is developed.According to the experiment in two coal mine, with the measurement of borehole trajectory parameter, the natural gamma can be used to recognition stratu m of coal formation strata, and the borehole trajectory can be drilling along the predetermined direction in the objective strata with the number of branch holes is reduce d.The system and drilling technology will provide effective means for improve coal drilling meeting efficiency, explore the formation geological information of mine, ensur e the safety and efficiency of drilling construction.