Abstract: Bayan obo super large Fe-RE-Nb deposit, associated with a large amount of fluorite and other resources. At present, the multi-element quantitative analysis method is used in the evaluation of mine resources, which can not objectively characterize the mineral composition and occurrence state of available resources. In order to determine the occurrence form of elements and the content of magnetite and fluorite minerals more accurately, this study uses the powder crystal X-ray diffraction K-value method for quantitative analysis, and uses dolomite as the reference material to prepare 1: 1 proportion of single mineral samples of magnetite, fluorite and dolomite produced in Bayan Obo, the reference intensity of magnetite with dolomite as the reference is K_Fe3O4 = 0.61, and the reference intensity of fluorite is K_CaF2 = 2.51. At the same time, the K value of other common co-minerals in Bayan Obo is selected. In order to realize the semi-quantitative analysis of the mineral content in different ore types of Bayan Obo, the correctness and applicability of the improved optimization K are verified by testing the known standard samples. Based on the quantitative analysis data of a large number of actual core ore samples, a three-dimensional model of spatial distribution of magnetite and fluorite minerals in Bayan Obo main mine was obtained by Kriegin interpolation method, and the spatial distribution characteristics of resource minerals were preliminarily presented. It is speculated that there is still a huge prospecting potential in the deep part of the mine area. X-ray powder diffraction quantitative analysis technology can directly study the semi-quantitative analysis of minerals in recoverable resources, which explores a new solution for precise mining and comprehensive utilization of resources, and also provides an important technical reference for the optimization of mineral processing process.