Abstract：The Tangjiaping Mo deposit in Henan Province is located in the Dabie orogenic belt. In quartz three types of fluid inclusions can be observed, namely CO2-rich (bearing) fluid inclusions, aqueous solution fluid inclusions and daughter-crystal-bearing fluid inclusions, based on the petrography, microthermometric measurement and Laser Raman microprobe analysis. The homogenization temperatures vary from 126.7°C to 472.1°C, the calculated fluid salinities cluster in two ranges, i.e., (0.18-14.21) wt% NaCl.eqv and (33.10-54.37) wt% NaCl.eqv, with densities changing from 0.38 to 1.21 g/cm3. Daughter minerals, mainly halite and metallic sulfide, can be recognized in fluid inclusions. The homogenization temperature and salinity of fluid inclusions reduce gradually outward from the center of ore-forming porphyry system. From early to late the fluid system evolved from and high temperature and high salinity to low temperature, and low salinity; and the trapped pressure reduced, indicating the mineralization depth became shallower gently. The Re-Os isotopic model ages of molybdenite are between 113 Ma and 118 Ma, about 10 Ma later than the crystalline age of the Tangjiaping granite porphyry. The ore-system was formed in waning stage extension setting of the inter-continental collision between Yangtze Block and North China Block.