Migration and distribution changes of CH, O, and N moieties in Dongming lignite (DL) derived petroleum ether-extractable portions (EPs), including cyclohexane (EPC), ethanol (EPE), and cyclohexane/ethanol (EPCE) systems were focused on in this work. Overall, EPC and EPE are rich in aromatics with short side-chains, while EPCE has the highest aromaticity. The gas chromatograph/mass spectrometer (GC/MS) analysis indicated that CH, >C-O-, and >C=O are three main parts. Alkanes in EPC are mainly concentrated in C11-C31 and the pristane/phytane ratio is 0.7, indicating the early anaerobic diagenesis of DL. Arenes are dominated by mono- to tricyclic compounds. The identification of these native compounds with low aromaticity implies the low coalification degree of DL. In addition, >C-O- and >C=O moieties predominate in EPE and EPCE. The differences in characteristic oxygenates, such as phenols and acetophenones, further indicated that ethanol involves in the cleavage of >Cal-O-Cal<, >Cal-O-Car<, and >Cal-Cal< bridged bonds in DL. GC/MS-undetectable oxynitrides, such as N1O1 and N2O1-4 species, were also discovered by Orbitrap MS. The compositional changes of O/N-containing species are related to source differences: (1) Step 1: the release of intrinsic fragments, (2) Step 2: the cleavage of weak O/N-containing covalent bonds, and (3) Step 3: the cleavage of covalent bonds with higher bond dissociation energies and the dissolution of macromolecules. The investigation on the changes of CH, O, and N moieties during the three-step mild degradation is beneficial to the secondary upgrading and value-added utilization of DL-derived soluble portions.