Methods of acid-base separation and extrography were used to decompose shale oil of Longkou oil shale (LSO), Shandong province, and coal tar of Shenmu coal (SCT), Shanxi province, both China, into acid, base and neutral fractions. The molecular structure and mass distribution of the oxygen compounds present in LSO and SCT were investigated using gas chromatography-mass spectrometry (GC-MS) and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The results of GC-MS showed that oxygen compounds in the acid fractions of LSO and SCT were phenols, indanols, naphthols, phenylphenols, fluorenols and phenanthrenols, and their derivatives, while oxygen compounds in neutral fractions 4 and 5 were aliphatic ketones, esters and minor aromatic ketones. The results of ESI FT-ICR MS demonstrated that in LSO, O-1, O-2, O-3, N1O1, N1O2, N-1 and N-2 compounds were determined with O-1 and O-2 compounds as the most abundant. SCT contained O-1, O-2, O-3, O-4, O-5 and O-6 compounds, while O-2 and O-3 compounds dominated.