To deeply understand the changes of char microstructure, the pyrolysis experiments of Huolinghe lignite(HLH), Jixi bituminous coal(JX), Datong bituminous coal (DT) and Jincheng anthracite (JC) were carried out at 25～1 600 ℃. The microstructure information of char was obtained by X-ray diffraction (XRD) and Raman spectroscopy (Raman), of which the relationship was studied. The result demonstrates that the microstructure changes of char have obvious three stages: depolymerization and liquidity, thermal condensation and aromatization, and graphitization. When L_a ＜3 nm, I_D1/I_G and I_D4/I_G increase with the increase of L_a; When L_a>3 nm, I_D1/I_G and I_D4/I_G decrease with the increase of L_a, indicating that the mode of connection and the number of defects are relate to the change of the size of aromatic layers at different scales. L_c is inversely proportional to I_D3/I_G and the total integrated area of Raman, indicating that the amorphous sp² carbon atoms exist in the interlayer of the aromatic layer, which is related to the activity of the aromatic structure.