///The bauxite deposit in Wuzhengdao area is sedimentary bauxite deposit of paleo-weathering crust which was formed by weathering. Based on the findings of ore X-ray diffraction analysis and the electron probe microanalysis (EPMA) on ore bed rock and ore-rock in Wachangping, this paper draws up a triangular diagram of Al₂O₃-SiO₂-FeO and elaborates on weathering and mineralization mechanism of bauxite. The main conclusions have been reached as followings: The essential condition of mineralization of bauxite is weathering. Weathering of mother rock is such a process that Si is continuously dissolved, transported and lost, while Al and Ti are relatively remained, remigrated, settled and enriched. The mineralization of bauxite is affected by factors such as climate and geographical environment during the weathering period. The scale of ore deposit and the quality of ore are closely tied to weathering duration, storage condition, and desilica-allitization.