The paper presents the geochemical characteristics of trace elements, REE and oxygen isotopes of kaolin rocks. According to a study of the sequence, petrology, mineralogy and geochemistry, kaolin rocks in coal measures may be divided into bauxitic kaolin rock and tonsteins. Bauxitic kaolin rock has higher the contents of trace elements, REE and oxygen isotopes and its REE pattern is similar to that of the typical NASC with negative Eu anomaly, which suggests that its source rocks are the weathering product of the weathering crust. Tonstein has lower contents of trace elements, REE and oxygen isotopes the REE patterns of some tonsteins are similar to that of the typical NASC, which suggests that the source rocks are similar to bauxitic rocks. The REE patterns of other tonsteins are different from the typical NASC REE pattern with no apparent Eu anomaly which suggests that the source rocks are pyroclastic sediments.