The Dongxi gold deposit is an important epithermal gold deposit in the Tongbai-Dabie orogenic belt, central China, with reserve of >5 tons(t) Au. It belongs to a suite of low-sulfidation epithermal systems associated with the volcanism. Gold mineralization is hosted in the Early Cretaceous andesite, and consists primarily of auriferous calcite-quartz veins that are confined to the NW-trending faults. The mineralization process is composed of two stages, i.e., coarse grained calcite veins (Stage Ⅰ) and quartz + calcite veins (Stage Ⅱ). Primary fluid inclusions in calcite include three types:monophase vapor, monophase liquid, and two-phase liquid-rich inclusions. The early-stage fluid inclusions have low homogenization temperature (128~172℃) and low salinity (0.35% to 0.92%), while the late-stage fluid inclusions have homogenization temperatures of 105~160℃ and salinities of 0.18%~0.92%. The temperatures and salinities of ore-forming fluids tend to decrease progressively. The ore-forming fluid seems to be the mixture of the magmatic and meteoric components. The crystallization age of the ore-bearing andesite has been fixed at 126.7±1.4 Ma (1σ, MSWD=0.95) according to U-Pb analysis of zircons by LA-ICP-MS. The Dongxi deposit might have been formed in a lithospheric extension and mantle upwelling setting, which provided abnormally high heat and fluid fluxes necessary for gold mineralization.