The results on the study of aromatic abundance in rock sample with ruby laser-pyrolysis gas chromatography (LPGC) are given. Experimental data show that aromatic abundance in rock sample can be decided by the relative abundance of G2H2 produced from LPGC. Accordingly, this provides a rapid and simple LPGC method for determining the oil-bearing rock in sedimentary rocks. In this paper, preliminary theoretical analysis from the view-point of plasma mnti-cheroistry reaction processes is .made on laser pyrolysis mechanism and others.