The Xianglushan copper deposit in Weining of northwest Guizhou is located in the copper bed between the top of the third unit of Emeishan basalt Formation and the bottom of Xuanwei Formation, and belongs to basalt type copper deposit. In order to study the geological characteristics of copper-hosting strata and mineralogical and petrological characteristics of copper-hosting rocks, the authors carried out rock-mineral determination, scanning electron microscope and electron microprobe analysis systematically in combination with field geological survey. The results show that the ore minerals of lithic siltstone are mainly composed of chalcocite, etrahedrite, bornite and malachite, and gangue minerals are mainly feldspar, quartz, chlorite and carbonaceous materials; the ore minerals of volcanic breccia are mainly composed of pyrite, bornite, chalcopyrite, chalcocite, tetrahedrite and malachite, and gangue minerals are mainly quartz, chlorite, dolomite and clay minerals. According to main mineral content, primary ores can be divided into three natural types, i.e., natural copper + chalcocite + hematite ore, natural copper + chalcopyrite + tetrahedrite ore and chalcopyrite + bornite + hematite ore. On the basis of mineral assemblages and intercalation relationship, mineralization can be divided into hydrothermal stage and supergene stage. The sequence of ore minerals at the hydrothermal stage is bornite→chalcopyrite→tetrahedrite→natural copper→chalcocite. At the supergene stage, malachite, hematite, hematite, ilmenite and limonite have been formed.