Abstract: The origin of the acidolytic hydrocarbon gas in carbonate rocks and its geochemical significance are studied in this paper. The study shows that aci-dolytic hydrocarbon gas represents the gas bound in carbonate minerals. Its origin is rather complicated and is affected by various factors among which epigenesis is the most outstanding one. In addition, according to the analysis and the study of its geochemical characteristics, the content of the acidolytic hydrocarbon gas bears no relation to the abundance and the maturity of the organic matter of the source rock, as well as to the lithology and the texture of the source rock. These facts underline the complex nature of the acidolytic hydrocarbon gas.