Abstract: The carbon dioxide gas field in Huangqiao,North Jiangsu Province is one of the largest ones which have been developed and utilized at present in our country.Its geologic reserves is 260×10⁸m³,and its basic explored reserves is 64×10⁸m³.The deep of the field consists of stratified and massive gas pools,and the shallow consists of Helium-rich natural gas pools.The composition and isotopic data of the field indicate that carbon dioxide comes from deep mantle.Gas pools are mainly formed by migration and accumulation through fissures.They have later pool-forming times.