Abstract: In order to clarify the geological characteristics，mineral properties and formation mecha⁃ nism of Liji kaolin deposit of Shangcheng in Henan Province，and to provide a theoretical basis for regional similar mineral exploration，this study adopted methods such as full-hole systematic sampling of boreholes， X-ray diffraction analysis，automatic mineral analysis and geochemical profile measurement to conduct a comprehensive analysis of the mineral body morphology，mineral composition，element migration patterns and formation conditions. The results show that the mineral body is located in the weathered crust of the Ear⁃ ly Cretaceous porphyritic rock and is produced in a layered manner，with an average thickness of 15.28 m; the ore type is sandy kaolin，with quartz and kaolinite as the main minerals，and the average Al₂O₃ content is 14.53%; the vertical direction can be divided into three geochemical zones of a strong weathering leaching zone，a secondary enrichment zone and a weak weathering zone. The study believes that this deposit belongs to the weathering residual subtype，and its formation has undergone two stages of pre-formation of endoge⁃ nous hydrothermal alteration and subsequent weathering leaching enrichment. It is controlled by multiple factors such as rock composition，structural fractures and warm and humid climate. This discovery enriches the types of kaolin deposits in Henan Province，indicating that the volcanic rock area at the northern foot of the Tongbai-Dabie orogenic belt in the late Mesozoic has considerable exploration potential，and can pro⁃ vide backup resources for the ceramic and building materials industries.

Key words: weathering residual type, kaolin deposits, geological characteristics, formation mecha? nism