Abstract: On the basis of study on the petrographic characteristics of coal2^-2 in Shenmu Coalfield, three types of peat swamp are recognized, i.e., open herb swamp, terrestrial forest swamp and wet forest swamp. peat swamp was evolved from the shallow lake on delta plain and had involved three evolutional stages. Herb was the main coal-forming plant at the early stage, but arborescent vegetation was dominant at both the middle and late stages. Forest fire and flooding events frequently occurred at the middle stage.