Abstract: A systematically comparative study on the kerogen of low mature, matured, over matured and thermal analogue by TEM and conventional geochemical methods is made in this paper. We have studied the secondary bio-facies and the molecule's orientating arrangement of kerogen by the high identification and magnification of TEM and by the method of selected area diffraction (SAD) and dark field (DF). It has proved that the secondary bio-facies and the molecule's orientating arrangement of degradation of kerogen is important basis for dividing the types of kerogen and valuing the potential to produce oil of kerogen. The important attainment of the study is to have found a most reliable basis for dividing the types of over matured kerogen and valuing its potential to produce oil.