Abstract: Based on analysis of coal petrological and petrographical properties of Coal Seam 1 and Oil Shale Seam 1 from Huangxian Tertiary brown coal and oil shale bearing basin,it is indicates that,coal seam 1 was formed in a forest swamp with fairly deep water;oil shale Seam 1 in a lake swamp,and the sea transgression controlled the fluctuation of the water level,further affecting the evolution and alternation of plant groups within swamps.