During the core drilling operation in the iron mine project of Taliabu Island, Indonesia, the formations drilled were with the trait of hydrophilic expansion and collapse as mudstone, shale and clay rock; with the trait of hydrophilic dissolution as tuff and ash rock; with the trait of “slipping” as chloride quartzite, and with the trait of difficult coring as fine iron ore. Downhole accidents like jamming, sticking and so on easily happened. Through bold exploration, a set of specific core drilling procedures in this area was developed with good technical results. The paper introduced the core drilling technology for this project in detail.