Objectives: There is a display and geochemical difference between lower thick layer and upper rhymic layer which respectively relatives to different genesis, understanding to the difference between characteristics will be beneficial for the future exploration and study on the Permian bauxite. Methods:Based on the field observation and study of ore structure ，and combined with comparative analysis of elemental geochemistry, this paper discusses the stratification rule of the sedimentary bauxite in west Guangxi. Results: The Permian bauxite deposit In western Guangxi has a binary structure which consists of lower thick layer and upper rhymic layer. The major ores in lower layer are massive bauxite, oolitic, and clastic one, The major ores in upper layer are dense bauxite and then clastic one, and a wash surface is observable covering on the lower thick layer. The content of Al2O3,Fe2O3,TiO2 in lower thick layer obviously are more than upper rhymic layer, SiO2 is 4 times more, and the content of CaO+MgO+K2O+Na2O in upper rhymic layer is 10 times more. of trace elements, Ba, Rb. Sr, Li are more in upper rhymic layer, inert components of enrichment of Sc, Cr, Ga, Nb, Hf, Ta, V, Zr, ∑REE are more in lower thick layer than upper. Conclusions: The whole bauxite was product of “accidence—process” substage of “Emeishan mantle plume——Dongwu movement” stage. the first substage was balance stage named “magma—deplanation” in which the lower thick layer had been formed from highly mature crust of weathering, latterly came the second unbalance stage of “magma—deplanation” in which the upper rhymic layer had made up by less mature crust of weathering, the maturity of crust of weathering decided the difference in stratiform and geochemical mutation between lower and upper layer. Acknowledgements: Financially supported by the project Small talent highland of deep exploration for critical mineral resources in Guangxi and the subproject of China Geological Survery (CGS) Geological and mineral resources survery of Nanling Metallogenic Belt Research on target-screening for exploration in the area of West Guangxi (No. 1212011085411 )