Abstract: The authors studied the petrology, mineralogy and geochemistry of kaolin rock in Late Paleozoic coal measures in northern Shanxi. The major types and accomudation horizons are: ① bauxitic kaolin rock at the base of the Benxi Formation, ② tonsteins in the Taiyuan Formation, and ③ tonsteins in the Shanxi Formation. The differences in petrology, mineralogy and geochemistry of different horizons are related to the genesis and source rocks of the rock.