Abstract: The hydrocarbon-generating potential of vitratn and clarain is studied by the means of coal Petrology and organic geochemistry,and their geological origins are also discussed with their molecular fossils. As a result,the clarain’s potential of preducing hydrocarbon is superior to the vitrain’s,and the groundwater level,the degrees of reduction and gelification in the Peat swamp in which the clarain deposited are respectively higherthan those of the vitrain swamp.In addition,the acidity degrees in theie swamp water are also somehow different during their deposition.