Abstract: In view of the limitations of the individual methods used in oil/gas geochemical explorations,the optimization of organization of the various methods would bring the advantages of the geochemical exploration into full play. The main methods of the geochemical exploration and the practices at home and abroad are introduced in this paper. Based on the available informations and the reliabilities of the different oil/gas indicators, it is suggested that the optimum organization of geochemical methods should take the hydro-geochemistry method as the main body,supported by gaseous hydrocarbon method, methane isotopic method, AC method, ultraviolet absorption spectroscopy and fluorescence spectroscopy. Finally,the applications of the above methods and the relationships between them are also discussed with examples.