The preliminary survey hole for the geothermal resource feasibility preliminary survey project in the Shilipu area of Xiangning County, Shanxi Province, was forced to change the hole structure due to the complex situation of the deep hole section, which made the original φ152mm oil drilling swivel-type double-tube core drilling tool useless. As a result, a φ131/79mm swivel-type double-tube core drilling tool has been developed. On the basis of analysis of the mechanical properties of the core drilling string, with field use of the drilling tool, adjustment of equipment parameters, and improvement of the drilling tool water passages and other deep hole core drilling aspects, good effect was achieved in continuous coring through the whole Ordovician and the underlying Cambrian layers. In this paper, the actual coring performance of the special core drilling tool in the deep hole section is also statistically analyzed and summarized.