The Taihexian Pb-Zn deposit is located in southeastern Hunan Province. In order to understand its fluid properties and evolution and discuss its metallogenic mechanism, the authors conducted field investigation and analyzed the ores of different metallogenic phases by such means as fluid inclusion petrography, microthermometry and laser Raman microprobe. The results reveal the existence of three ore-forming stages in the Taihexian Pb-Zn deposit, characterized by vein cutting relation and mineral assemblages of quartz-pyrite-arsenopyrite (the early stage), quartz-Pb-Zn polymetallic sulfides (the middle stage) and quartz-calcite-pyrite. Four main types of fluid inclusions were distinguished in the hydrothermal quartz, i.e., liquid-rich inclusions (type Ia), vapor-rich inclusions (type Ib), carbon-aqueous two-phase inclusions (type Ⅱ), and carbon-aqueous three-phase inclusions (type Ⅲ). Microthermometic data show that the homogenization temperatures of the fluid inclusions from the early stage to the late stage are gradually decreased, from 235~349℃, through 159~272℃ to 128~205℃, with the corresponding salinities being 2.03%~7.44%, 1.39%~10.86%, and 1.39%~7.58%. Raman microspectroscopic studies of the fluid inclusions show that the main component of aqueous inclusions in quartz-pyrite-arsenopyrite, quartz-Pb-Zn polymetallic sulfides and quartz-calcite-pyrite is H₂O, followed by CO₂, with a little reducing gas CH₄ and N₂. The metals precipitation resulted from fluid immiscibility caused by CO₂ escaping at the early stage, fluid mixing caused by meteoric water and interlayer water at the middle stage and natural cooling of fluid system at the late stage.