Abstract: For a key project during the 8th "Five-Year-Plan", the authors made a systematic study of the geochemical data collected from the major oil/gas-bearing basins in China. It is considered that the reliability of anomalies would be improved by studying the variation of geochemical background value with an oil/gas-bearing basin as a basic unit; and that it is important to acquire oil and gas information scientifically and use geochemical technology correctly; and that six indicators can be summed up including the identification of the characters of hydrocarbon gases in natural gas, and spectrometric parameters etc, as well as geophysical-geochemical prospecting technologies applied to explore oil/gas directly; and that the application of the technology with well geochemical logging has promising prospects.