Baiyanghe uranium deposit is a typical uranium- polymetallic deposit in Xinjiang. In order to find out the mineralogical characteristics of primary uranium minerals and to investigate the forming environment and preservation of pitchblende in detail, this paper carried out mineralogical analysis on pitchblende by utilizing polarizing microscope, scanning electron microscope (SEM), electron probe (EPMA) and other methods, and study of the black fault gouge spatially related to the primary uranium orebodies using Laser Raman spectrometer and carbon- sulphur detector. The results show that the primary pitchblende mainly occurs in the hydrothermal veins with main ore fabrics of cataclastic, granitic crushing, porphyroclastic, and metasomatic reaction rim textures. The chemical compositions of pitchblende are very complicated as pitchblende underwent varying degrees of transformation by fluids. With fluid transformation increasing, the contents of UO2 and PbO decrease and Nb2O5 and ZrO2 increase, indicating that the uranium was mobilized and migrated during the transformation processes and Nb and Zr elements were brought in by fluids. Further investigation shows that the carbon- bearing fault gouge may provide favorable conditions for the precipitation of pitchblende from reduction of soluble U6+ complex, and also play a protective role in the preservation of pitchblende.