Dabeiyu Gold Deposit is a typical gold deposit in the northern part of Taihang Mountains.The ore-forming fluid characteristics of Dabeiyu Gold Deposit are studied to analyze the genesis of the deposit.The ore body is mainly distributed in the glide-detachment faults between Neo-Archean Fuping Group and Meso-Proterozoic Changchangian Gaoyuzhuang Formation,and the Gaoyuzhuang Formation dolomite fracture alteration zone.The minera-lization process can be pided into 4 stages,namely pyrite-quartz,quartz-pyrite,quartz-polymetallic sulfide,and quartz-carbonate.The ore-forming fluid inclusions mainly include CO2 inclusion and gas-liquid inclusion.The tempera-ture during the main mineralization stage ranges from 262.8 ℃ to 346.4 ℃,the salinity ranges from 8.6  % to 12.3  %,and the density ranges from 0.77 g/cm3 to 1.08 g/cm3.The ore-forming fluid is characterized by medium-low tempera-ture and medium-low salinity CO2-H2O-NaCl and H2O-NaCl systems.The C,H,and O isotope compositions show that ore-forming fluid mainly consists of magmatic water and mixes with atmospheric precipitation.Based on the metallogenic theory of mantle branch structure,Dabeiyu Gold Deposit belongs to the glide-detachment fault type gold deposit.