Abstract: Over a long period of time,whether coal can be degradated by anaerobic microorganism into gas,has been a controversy concerning geology,method and technique in geoscience.The paper deals with this subject based on the simulation experiments on biogas.It is proved that coal can be degraded by anaerobic microorganisms.Furthermore the paper discusses the significance of gas derived from the anaerobic degradation of coal for the selection of prospect areas of coal bed gas.