The Shuangjianzishan super- large Ag- polymetallic deposit is the most representative hydrothermal silver deposit in the Daxing'anling metallogenic belt and the largest silver deposit discovered in Asia. The hydrothermal mineralization of this deposit can be divided into two periods, Period I and Period II. Period I can be further divided into three stages: stage I- 1 (pyrite+galena+sphalerite+silver bearing mineral+quartz assemblage hosted witin NW- trending veins), stage I- 2 (galena+silver bearing mineral+sphalerite+quartz+calcite assemblage hosted within NNE- trending veins), and stage I- 3 (Au- bearing quartz+calcite vein assemblage within near- EW trending veins. Period II is nonmineralized quartz veins mainly being quartz+calcite assemblage. The fluid inclusions in the deposit are dominated by L- type and V- type, generally belonging to medium- low temperature, low salinity fluid. The homogenization temperature of stage I- 1 ore- forming fluid inclusions ranges from 171℃ to 280℃, with an average of 228℃,and salinity of 0.53%~12.73% (NaCl eqv ) with an average of 3.48% (NaCl eqv ). The homogenization temperature of stage I- 2 ore- forming fluid inclusions ranges from 109.3 ℃ to 258.0℃ with an average of 193.3℃ and salinity of 0.18%~22.38% (NaCl eqv ) with an average of 4.20% (NaCl eqv ). The homogenization temperatures of fluid inclusions in period II range from 238.7℃ to 362.9℃, with an average of 275.9℃ and salinity of 0. 35%~2.24% (NaCl eqv ) with an average of 1.05% (NaCl eqv ). δ13 C and δ18 O SMOW of calcite range from -11‰ ~-7.4‰ and 1‰~4.5‰ respectively. δD H 2O and δ18 O H 2O of quartze and calcite vary from -145‰ to -65‰ and from -12.5‰ to 4.6‰, indicating that the ore- forming fluid is a mixed source. The 4 0 Ar/ 36 Ar ratio of metal sulfide ranges from 294.75 to 303.92 and the 3 He/ 4 He ratio ranges from 0.25 to 0.81 Ra, suggesting its origin of crustal source. The ore- forming fluids of the Shuangjianzishan deposit have the characteristics of multiply pulsed, multi- stage evolution and multi- source, presenting an evolution trend from relatively high temperature and high salinity to low temperature and low salinity. The mixing of initial magmatic water and atmospheric precipitation may be the main mechanism of metal precipitation in this deposit. The Shuangjianzishan deposit is a meso- epithermal Ag- polymetallic deposit related to crustal magmatism.