Haigou gold deposit is a typical orogenic gold deposit. There are a reasonable amount of fluid inclusions in the gold deposit,including three types: CO2-H2O-Na Cl inclusions,pure CO2 inclusions and Na Cl-H2 O inclusions,of which most of them are CO2-bearing inclusions. The fluid salinity is 1. 43%- 9. 08%,mainly concentrated in the range of 4. 69%- 5. 41%,the density of CO2 is 0. 69- 0. 80 g / cm3,indicating that the mineralization fluid is low-medium salinity and low density fluid. A series of studies on gold-bearing quartz vein and fluid inclusions show that there exists a positive correlation between the degree of the gold mi-neralization and the amount of CO2 in the inclusions,which means the more CO2-bearing inclusions there are,the higher the content of gold is. CO2 is mainly derived from mantle fluid,and the ore-forming fluid should be derived from mantle fluid and the crust shallow fluid. The conclusions have important denotative meaning on the metallogenic mechanism of orogenic gold deposit and the deep prospecting on metal deposit. There are a reasonable amount of fluid inclusions in the gold deposit, including three types: CO2-H2O-Na Cl inclusions, pure CO2 inclusions and Na Cl-H2 O inclusions, of which most of They are CO2-bearing inclusions. The fluid salinity is 1. 43% - 9. 08%, mainly concentrated in the range of 4. 69% - 5. 41%, the density of CO2 is 0. 69- 0. 80 g / cm3, indicating that the mineralization fluid is low-medium salinity and low density fluid. A series of studies on gold-bearing quartz vein and fluid inclusions show that there exists a positive correlation between the degree of the gold mi-neralization and the amount of CO2 in the inclusions, which means the more CO2-bearing inclusions there are, the higher the content of gold is. CO2 is mainly derived from mantle fluid, and the ore-forming fluid should be derived from mantle fluid and the crust shallow fluid The consequences have important denotative meaning on the metallogenic mechanism of orogeni c gold deposit and the deep prospecting on metal deposit.