Abstract: Taking Balochistan lignite (BL) in Pakistan as the research object, the chemical formula of BL is C167H130O53N2S according toelement analysis. The existing forms of oxygen, nitrogen and sulfur in BL organic structure were analyzed by X-ray photoelectron spectroscopy (XPS). The characteristics of the main functional groups in the organic structure of BL were studied by Fourier transform infraredspectroscopy (FT-IR). The main functional groups in the aliphatic structure of BL are —CH and —CH2. The main substituted forms ofbenzene ring in BL are trisubstituted and tetra substituted. The carbon skeleton structure of BL organic structure was explored by13C-NMR. In the molecular structure of BL, the ratio of aromatic bridge carbon to pericarbon XBP is 0.21, and the carbon is mainly composed of aromatic carbon and fatty carbon, of which the mass fraction of fatty carbon is 53.23%, and the proportion of aromatic carbon is41.93%. The aromatic structure is mainly benzene ring and naphthalene ring, oxygen is mainly in the form of carboxyl, carbonyl, etheroxygen and phenolic hydroxyl, while nitrogen is mainly in the form of pyrrole nitrogen, and sulfur is mainly thiophene. A two-dimensional molecular structure model of BL was established. The three-dimensional structure of BL molecular model was constructed by hydrogenation saturation through materials studio, and the molecular model was further optimized. The space effect is significant, and the BL three-dimensional structure model with the lowest energy is obtained. It is found that van der Waals energy is the key factor for the stability ofBL molecular structure. The calculated 13C—NMR spectra of BL model structure are basically consistent with the experimental spectra,which verifies the rationality of the BL structure model.