According to the tectonic development in a molybdenum mining area of Inner Mongolia with complex geological conditions of hard formation, broken core, borehole diameter shrinkage, leakage, collapsing and block falling, the technical experiences of drilling construction for wire-line coring in hard, brittle and broken formations were summed up. Analysis was made on borehole structure, mud configuration, flush fluid selection, drilling equipment and new SYZX75 2 ( 77) type wire-line coring hydro-hammer drilling tool to solves the leakage, collapsing, block falling and drilling difficulties in hard “skid” formations. The paper emphatically elaborates the high strength dehydration blocking test, which can improve drilling conditions in complex formations and drilling production efficiency to ensure the drilling safety.