The Yanzigou gold deposit in Danbacounty, Sichuan, is located in the Songpan-Ganzêorogenic belt. The ores can be divided into quartz vein gold ore and layered carbonaceous slate gold ore. Gold mineralization consists of pre-mineralization, main mineralization and post-mineralization periods. The fluid in the Yanzigou gold deposit is acidic and belongs to a CO2-H2O-NaCl system.Fluid inclusions can be divided into two types. Fluid inclusions in pre-mineralization and main metallogenic period have the typical characteristics of orogenic gold metamorphic hydrothermal fluid: medium homogenization temperature, low salinity, low density and high CO2. However, the fluid inclusions of post metallogenic period shows the characteristics of meteoric water, characterized with low homogenization temperature range, low salinity, low density and low CO2. During pre-mineralization and main mineralization periods,gold was mainly transported as \[Au(Cl)4\]- complex compound and \[Au(HS)2\]-, respectively. During the transition process from compression to transpression, the P-T conditions of fluids changed greatly, coupled with penetration of meteoric water into tensile fractures, resulting in boiling and mixing of fluids. With increasingof gold-sulfur complex content, and change of physical and chemical conditions such as PH, Eh, fO2, and fS, ore-forming materials started to precipitate and form ore bodies. According to the characteristics of the ore-forming fluids, the Yanzigou gold deposit belongs to orogenic gold deposit.