Abstract: The small sized Maiditianxin copper deposit, located in Yangbi County, Yunnan Province, is mainly controlled by faults. The orebodies occur in the lower member of Jingxing Formation, Lower Cretaceous (K₁j¹). The ore veins are hosted in the medium-thick layered quartz sandstone, which is simply fading altered sandstone. The orebodies are small, with oxidation rate between 73.61% and 92.64%, belonging to high oxidation ore. By preliminary analysis, the genesis of the deposit is sedimentary-hydrothermal reformed type, closely related to the interbedded structural alteration zone in the "West Yunnan red beds".