Abstract:The Tugurige gold deposit is a large tonnage quartz- vein type deposit in the western part of the Xing'an- Mongolia Orogenic Belt (XMOB). The gold mineralization and calc- alkalic granitic magmatism of this deposit have very close genetic relationships. Te- rich gold deposits associated with calc- alkalic granitic magmatism are relatively rare, and this kind of Te- rich gold deposits is rarely reported in the XMOB. Based on optical microscope and electron probe micro- analysis (EPMA), for the first time a large number of the tellurides were discovered in the ore samples of the Tugurige gold deposit, such as calaverite, stutzite, petzite and native tellurium. The gold and silver of this deposit are primarily occurring as Au- and Ag- tellurides, with a small amount of native gold and electrum. The main mineralization stage (Ⅱ, auriferous quartz- polymetallic sulfide stage) of this deposit can be divided into three sub- stages from early to late, namely,Ⅱ1, Ⅱ2, and Ⅱ3- stage. The mineral assemblages of Ⅱ1, Ⅱ2, and Ⅱ3- stage are coarse pyrite- stutzite- petzite- native tellurium- galena, fine- grained pyrite- calaverite- petzite- altaite, and native gold- electrum- galena, respectively. The mineral assemblage characteristics indicate that, in Ⅱ1- stage of mineralization, the lgfS2 and lgfTe2 values of ore forming fluids ranged from -13. 5 to -10. 9 and from -10. 5 to -9. 4. The lgfS2 and lgfTe2 values of ore forming fluids in Ⅱ2- stage ranged from -16. 7 to -12. and from -11. 2 to -9. 4, respectively. Fluid boiling and condensation of H2Te- bearing vapors were the dominant controls on precipitation of the Au and Ag telluride ores, and occurrence of inhomogenous native tellurium- sulfide mineral assemblages.