Rare earth element(REE) study of mud—shale of the Cretaceous Madongshan Formation in the Liupanshan Basin through 10 samples collected from the Well Guye- 1 in the basin. In this paper, we focus on REE characteristics and its geological significance. Methods: Samples for REE analysis were first crushed and ground to a particle size of less than 200 mesh, and measured by RTX2100 and ZSXPrimusⅡsreies X- Ray fluorescence spectrometry which made in Japan. Results: The results show that the total content of REE(∑REE) of mud—shale in the Madongshan Fm. varied from 125. 2×10-6 to 175. 1×10-6 with an average at 152. 9×10-6, which is slightly less than the content of NASC, the ∑LREE content is varied from 114. 4×10-6 to 160. 6×10-6with an average at 139. 7×10-6, while the ∑HREE content is varied from 10. 78×10-6 to 14. 69×10-6 with an average at 13. 28×10-6. Conclusions: Geochemical parameters such as ratios of LaN/SmN 、GdN/YbN、∑LREE/∑HREE indicate an obverious differentiation of ∑LREE and ∑HREE. The distribution of normalized REE patters show that the LREE is obviously richer than HREE. The obviously negative Eu abnormity and weak negative Ce abnormity indicated the diagenesis had a limited impact on REE The distribution of REE patters show that the sedimentary sources of mud—shale in Madongshan Fm. are relatively consistent, and the ∑REE—La/Yb chart means that its source rock is sedimentary rocks, and the negative Eu abnormity indicated this sedimentary rocks have granite provenance characteristics. The relationship of w(∑REE) with w(Al2O3), w(SiO2), w(TiO2)and w(CaO) show that the REE content are jointly controlled by the supply of near- source terrigenous debris, water- body element differentiation, and biological effects. The ∑REE, negative Eu abnormity, and Ceanom, δCe, LaN/YbN index show that the climate of the mud—shale in the Madongshan Fm. was warm and humid, the mud—shale is mainly deposited below the redox interface of water bodies with a certain depth. The stable and slow deposition rate providing a good conditions for the preservation of organic matter.