Abstract:The Baogutu porphyry copper deposit, a gold-rich porphyry copper deposit, is located on the margin of western Junggar Basin in Xinjiang. The average Au, Ag and Cu contents of the deposit are 0.25 g/t, 2.56 g/t and 0.30%, respectively. Two ore-forming stages have been observed. The early stage, during which Cu-Mo-Au assembly was formed, seems to have been the main mineralization stage. The latestage, during which the Cu-Au-Te-Bi assembly was generated, only occurred in local places of the ore deposit and was not large in scale, but it played the role of enriching the ore. According to the microscope observation and electron microprobe analyses of the polished sections and polished thin sections, the authors consider that at the early ore-forming stage, Au content was higher than Ag content, and these two elements existed homogeneously in sulfides as solid solutions, with no independent minerals formed. The late ore-forming stage was characterized mainly by the formation of argentiferous minerals and complex Cu-Au-Ag-Te-Bi minerals, with the major minerals being hessite, Bi-bearing hessite(?), Ag-bearing tetradymite (?), Ag-bearing wittichenite, electrum etc. These min-erals are present as slender veins superimposed upon earlier mineralization. Though limited in scale, the late stage mineralization played an important role in improving the economic value of the deposit.