Abstract: In this paper,Micro-FTIR is used to analysed and test fluorescence vitrinite,cutinite and resinite in a coal source rock sample,and their chemical structures and hydrocarbon-generating characteristics are quantitative analysed and studied by means of the IR partition chromatographic technology and the computer curve-fitting method.The results show that vitrinite has more C=O structure,and cutinite and resinite two have more aliphatic hydrocarbon structure (CH₂+CH₃);the chemical structures of monomacerals in coal rocks decide that they have different hydrocarbon-generating characteristics,that is,vitrinite mainly generates gas,cutinite and resinite mainly generates oil,and vitrinite and resinite have the feature to generate hydrocarbons and form low-mature oil in the earty stage.