Abstract: Separation and Identification of Biomarkers in Geological Body by GC/MSXiang Tongshou(Guangzhou Institute of Giochemistry,Chinese Academy of Sciences,Guangzhou 510640, China)Abstract:In the area of organic geochemical research, GC/MS has been more widely employed to analyse and to identify biomarkers in geological body due to its advantages both in the excellent separation ability of GC and in the precision in identifying organic compounds by MS. The present paper introduces the chemical preparation procedure and GC/MS operation applied to the analysis of dissolved organic compounds in geological body, and also gives the essential data of some important biomarkers in organic geochemical research.Keywords: biomarker, organic analysis, GC/MS