Abstract：The Muziyuan tungsten deposit is a medium-size quartz-vein type tungsten deposit in southern Jiangxi Province. The model using surface mica line and quartz line can be used in search for concealed quartz vein type ore deposit. Based on detailed petrographic observations, the authors carried out microthermometric and Raman microspectroscopic studies of fluid inclusions in wolframite-quartz veins of the Muziyuan tungsten deposit. Experimental results show that fluid inclusions in quartz have recorded at least two periods of fluid activities. These two kinds of fluid are of the high temperature, low salinity and low density NaCl-H2O fluid system and the low temperature, low salinity and medium density NaCl-H2O fluid system respectively. In the evolution process of ore-forming fluids in the Muziyuan tungsten deposit, high temperature stage experienced some boiling, resulting in the decomposition of the metal complex in ore forming fluids and ore deposition, whereas the low-temperature phase was mainly subjected to the natural cooling process, and the fluid mineral precipitation resulted mainly from the temperature decrease.