Abstract: Considering the drilling efficiency problem encountered by crossing holes in underground coal mine, the paper divided roof and floor rock stratum into three grades in order to facilitate the study of technology in underground coal mine: high hard rock (4≤f<8), sturdy hard rock (8≤f<15), super hard rock(f≥15). According to different grades of rock, the paper developed corresponding drilling technology and summarized corresponding optimal process parameters. Through a large number of field tests, the high strength PDC bit rotary drilling method was developed, which was suitable for high hard rock, at the same time the test drilling efficiency increased by about 1.6 to 2 times; the rotary-percussion drilling method was developed, which was suitable for sturdy hard rock, moreover, the test drilling efficiency increased by 50 times; the percussive-rotary drilling method was developed, which was suitable for super hard rock, meanwhile, the test drilling efficiency increased by 4 to 25 times.