Abstract: XRD and Raman spectroscopy were used to study chemical structure evolution of Shenmu coal in the main pyrolysis temperature range (450-750℃) and three pyrolysis atmospheres (N₂, H₂-containing and CO-containing). Correlation of structural parameters obtained by the two methods was compared. The results show that the char prepared by pyrolysis of raw coal in N₂ has a continuous increase in the size of carbon crystallites in the transverse direction, a gradual increase of spacing in the longitudinal direction, and a sharp change of stacking height around 650℃. Raman parameter A_D1/A_G increases, while A_G/A_all decreases, indicating a decrease in proportion of the ordered char structure. The H₂-containing atmosphere promotes the longitudinal development of the carbon crystallite structure, increases the conversion of small molecule groups and the ordered degree of char. The influence of CO-containing atmosphere on the carbon crystallite structure parameters is less than that of the H₂ atmosphere. But below 700℃, the dense carbon particles produced by CO-containing atmosphere due to carbon deposition are entrapped on the char surface, resulting in an increase in the ordered degree of char carbon. There is a certain correlation between L_c and A_G/A_all, and d₀₀₂ and A_D1/A_G of char; L_a has a good positive correlation with A_D1/A_G.