Abstract: The flotation fractions of a long-flame coal were obtained by heavy medium separation method, and its effect on regulation of sulfur and coke reactivity during pyrolysis of high-sulfur coking coal were investigated by FT-IR, Raman, TG, Gieseler fluidity, N₂ adsorption, XRD. The results show that the low density fractions contain more aliphatic side chains and unstable aliphatic structure, while the high-density fractions show higher amount of minerals and inert components. Low density fractions have the highest sulfur removal rate due to lower content of alkaline minerals and more aliphatic side chains. The medium molecular weight component in the low density fractions has little effect on properties of metaplast. Higher minerals and inert components in high-density fractions deteriorate the metaplast more obviously. Meanwhile, order of the coke's microcrystalline structure is reduced and the defect sites increase, and consequently, reactivity of the coke increases.