Strata breaking, fracture development, alteration diversity, water gushing and hard intact rock co-exist in Chaijiagou molybdenum deposit, and most of the geological design requirements are inclined holes. The technical difficulties were countered in drilling construction, such as water leakage, collapse and block falling, slow footage and serious inclined drilling. This paper summarizes the experience of drilling construction in borehole structure, flushing fluid solution configuration, wall protection and plugging, hard rock drilling, the use of weighted mud in water gushing formation and the precautions of inclined hole construction with vertical shaft drilling rig.