Coal is still the world’s major source of energy. Geological exploration for coal resources will ultimately go to the deeper earth， and wire-line coring drilling technology has always been the first option for deep exploration due to its high quality and efficiency in deep drilling. Currently， wire-line core drilling technology has not been fully used in the coalfield because of some technical problems with coalfield strata. However， measures can be taken to solve them. Water sensitivity is a common phenomenon in the coalfield’s geological exploration， leading to high sand and mud content in drilling mud and deteriorating performance of drilling mud. There are also problems associated with “water sensitive” and “sand damage” in coalfield wire-line core drilling， such as high pump pressure， high mud flow rate， severe erosion， serious negative effect from flushing fluid dynamics. The low strength and poor capacity of non-coal geological exploration standard drilling tools （drilling stems） cannot cope with the above adverse effects. Therefore， it is necessary to optimize the makeup of drilling mud for water-sensitive formation； more importantly， removal of sand and mud should be solved. In addition， it is necessary to break conventional thought and build a new system， such as enlarging the diameter of the drilling hole， increasing the clearance between the matching bit sizes， improving the power of the equipment so as to overcome the problems with high power.