This paper discussed the petrological characteristics and coal facies of No.6 coal seam from the Haerwusu Mine, Jungar Coalfield, Inner Mongolia by using of coal petrology and geochemistry. No.6 coal facies can be divided into 3 types, arid forest peat swamp （including two subfacies） and reed peat swamp, respectively. From bottom to top, the development of peat swamps present wavy changes, and three coal facies types appear alternately, with obvious thyme. According to the parameters, 11 secondary sequences were identified of the peat swamps of No.6 coal seam. The results indicate that the mire formed in brackish water-fresh water weak regression environment, changed in excess oxygen and poor oxygen, and reflected the characteristics of transition phase.
