According to the difficulties of wire-line coring drilling in complex formation of Dawanggou molybdenum mine with intense alteration, uneven hardness and gushing leakage, the wall protection was adopted by casing first and slurry secondly. The discussion was made on the selection of drilling equipments and tools as well as diamond bit parameters determination; wall protection with K + humate-containing drilling mud and plugging with inert stuffing were put forward and tripping pressure surge and suction damage to the hole wall decreasing measures were used with good application effects.