Two samples of organic clay complex，one is synthesized（sample No.0）and the other is natural（sample No.1with grain size less than2μm acquired from source rocks），are extracted by chloroform and suˉpercritical fluid successively.Analyses of extract volume，group composition，and GCˉMS were carried out and TOC，XRD，IR and thermal analysismethodswere applied to the residue to study the occurrence of organicmatˉter in source rocks and its significance to petroleum geology studies.The result reveals that the amounts of extract are quite different for chloroform and supercritical fluid.For the supercritical fluid，the dom inantGC peak of carˉbon shows a tendency ofmoving towards carbon with larger numbers，indicating a difference in characteristics of organicmatters revealed by different extraction agents.However，the TOC in the residue is stillhigh，showing that a significant amount of organicmatters still exist on clay surfaces after successive extraction processes.The XRD