Dafangshan-Huluyv Au mining area locates at the joint of the south end of North China platform and north Qinling orogenic belt.The mineral vein occurs in tectonic-altered fracture zone.Most of the fluid inclusions in each metallogenic phases are gas-liquid inclusions.Analysis on inclusions in each phase shows that the homogenization temperature of the inclusions in main metallogenic phases varies between 197℃ and 305℃,and the salinity varies between 10.98 wt%NaCl and 0.88 wt%NaCl.The gas component of fluid in-clusions contains large amount of H2 O and CO2 and minor amount of O2 and N2 .The ions in fluid inclusions are mainly K+、Na+、Ca2+、SO4 2-、Cl-.The study on the fluid inclusions shows that ore-forming fluids of Au deposit originated from the medium-low temperature fluids of multiple sources.