An ancient mine site for extracting multicolored pigments was discovered at the Flame Gorge of the SanWei Mountain, Dunhuang, which holds academic value for researching the sources of ancient mineral pigments in northwestern China. To determine the mineral species and spectral characteristics of pigments discovered there, we employed polarized light microscopy, X-ray diffraction, Laser Raman spectroscopy, and X-ray fluorescence spectroscopy to analyzethe pigment production. The results indicate that the mineral pigments produced from SanWei Mountain are natural minerals, primarily Fe₂O₃ (average 66%) and SiO₂, etc. Some of the samples are rich in silica-aluminum, and all of them have different degrees of loss-on-ignition. The main phases are hematite, goethite, and some jarosite. The gangue minerals include quartz, kaolinite, and clay minerals. The color phase of pigment minerals was further analyzed by Raman spectroscopy. The color phase of bright No.2 minerals was consistent with the main phase discussed above, namely jarosite and natrojarosite. All the reddish-brown samples except for No.4 contain α-Fe₂O₃, hematite, which causes the reddish-brown color. Sample No.4 contain sgoethiteand become sreddish-brown due to the presence of hematite, which is associated with yet is much stronger in color than hematite and, therefore, changes the color of sample No.4. In conclusion, the red mineral pigment produced at this ancient minesite is mainly hematite. The yellow mineral pigment is jarosite and natrojarosite. As an excellent pigment, jarosite is used in rock paintings and murals, but it has not been found in the frescoes studied in the Mogao Caves.This discovery has extended the dimension of yellow mineral pigments in northwestern China. It provides basic support for the subsequent pigment flow of the pigments produced in this mining and metallurgical site.