The geological conditions in Shanggong Gold Mine, Luoning, Henan Province are complex, where the strata are broken; in particular, the middle and lower parts are eroded into green mudstone, and will be dispersed, flaked, and collapsed when encountering water, making it difficult to drill. In view of the characteristics of the strata in the mining area, measures have been taken in aspect of equipment and material selection, borehole structure and drill bit selection with emphasis on application of the film-forming drilling fluid to solve the difficulty in coring. Remarkable results have been achieved, and some experience has been accumulated for drilling the complex strata in the future.