Depending on the summary of the geological characteristics of CO
2 gas produced from Huanghua Depression, the paper states that the CO
2 gas is a type of multiple sources.It can be either intergrowthed and accompanied with hydrocarbon gas and liquid hydrocarbon or hetero-growthed and accom-panied with oil/gas water in the pattern of water-soluble CO
2 gas of multiple sources,meanwhile,it can be accumulated to be highly concentration CO
2 gas and distributed on the high locations of petroliferous structures.The variations of CO
2 gas content and the geological characters of CO
2 gas producing can be used as a director for reconnaissance and exploration of the hydrocarbon gas and liquid hydrocarbon.