Abstract: Yindongpo gold deposit which is located in the middle part of Weishancheng AuAg ore belt in Tongbai County is a super large gold deposit and associated silver,lead and zinc.Petrographic,microthermometric and laser Raman spectroscopic studies were carried out on fluid inclusions in quartz from gold ores.The results show that three types of primary fluid inclusions occur in gold ores:vaporliquid two phase inclusions,CO2bearing three phase inclusions and vaporrich inclusions. Oreforming fluid is NaClH2OCO2 system with a little N2,CH4,H2S and H2.The fluid immiscibility is the main factor leading to the precipitation of ore materials.The homogenization temperatures and salinities of three types of inclusions range from 1692 ℃ to 3992 ℃ and 18% to 122%. The salinity of CO2bearing three phase inclusions is lower than that of vaporliquid two phase inclusions.The oreforming pressure of major mineralization phase is mainly 62-1263 MPa, corresponding to the depth of 52 km.The δ34S value of pyrite in the ore varies from 16‰ to 33‰，which is lower than δ34S value of pyrite in wall rock which varies from 33‰ to 62‰. It indicates that the sulfur in the ore may be derived from the mixing of mantle sulfur and wall rocks.

Key words: Yindongpo gold deposit, oreforming fluid, fluid immiscibility, sulfur isotope, orogenic gold deposit, Henan