Abstract: Gas chromatographic analysis of the fluid inclusion volatile in vein quartz from several gold deposits in Xiaoqinling gold field reveals that H,O and CO, are main components of volatile in the ore-forming fluid, and CH4, CO2, H2 and H2 S are minor ones. The gold-bearing fluid is significantly enriched in CO2. Variation of CO2 content bears close relationshipwith distribution of high grade ores.CO2 content of fluid inclusions in gold-rich ores(commonly more than 30 mole percent and CO2/H2O>0. 4)is higher than that in gold-poor ores. CO,content is typically less than 20 mole percent and CO2 /H2 is less than 0.2 in gold-poor ores. In addition,fluid inclusion volatile in gold-rich ores have a much higher concentration of redox gases (i. e.,CH4,CO and H2, etc.) CO2 content and CO2/H2O ration of fluid inclusion volatile may be a good exploration guide in deeper prediction of gold mineralization, and this method has achieved great successes in Xiaoqinling gold field.