Abstract: The latest study shows that Huangqiao area,Jiangsu Province is located at the concealed deep fault from Binhai to Tonglu.Trending in NS and developing along 120°E longitude.the fault extends more than 500km long and is 20～30km wide.With a transcurrent shear property, it almost vertically cuts the late Tertiary system down to the bottom of lithosphere,and provides a favorable path for the inorganic oil and gas from the depth to move up toward the surface. The CO2 from the CO2 gas field of Huangqiao was considered to be originated from the mantle(Dai Jinxing,1995；Xu Yongchang,1994；Chen Husheng,1999).The research results in this paper indicate that the CO2 of this gas field was not derived from the mantle,but resulted from oxidization of mantle CH4 on the way moving up toward the surface(-3000~0m).Like a quilt with cotton wad,the CO2 gas field of Huangqiao is considered to cover over the underneath inorganic oil and gas.A deep-seated oil and CH4 gas field with a large reserves of more than one billion tonnes should be concealed under the CO2 field of Huangqiao. The practica1 sense to build such a geochemical evolution pattern is that there should exist oi1 and gas fields below any CO2 gas fields,but with different depths and reserves.It is not only a typical pattern summarised from the evolution of oil and gas resources of Huangqiao area,Jiangsu Province,but also has a general significance in the global scope.The evolution stage of the upper crust in this pattern indicates that the inorganic CO2 gas field of Huangqiao area was not directly produced from the upper mantle,but was an inevitable result from oxidation of mantle CH4 under oxidizing condition.Therefore,a CH4 gas field or a condensated oil field,or both of them ,should be found below the CO2 gas field of Huangqiao.To search for the inorganic oil and gas deposits in Huangqiao area,the favourable site should be the space under the C02 gas field and at the depth between -5000m and – l0000m .This paper suggests a three-dimensional prospecting model for the inorganic oil and gas deposits in the unknown area,which is more economic and with higher efficiency.