There are lots of drilling and coring difficulties for exploration engineering in complex formations. The formation structure is usually unstable and broken with soft and hard layers interbedded, which makes the service life of drilling bit very short; and the accidents, such as hole collapse, block-falling, diameter shrinkage, leakage and water gushing, happen frequently, the drilling efficiency is hard to be improved. According to these problems, based on diamond wire-line coring drilling technology in current drilling engineering and by design improvement on diamond bit in tests, drilling efficiency and service life of drilling bit were both improved with drilling efficiency significantly increased and drilling accident reduced.