In this study, Yangquan (YQ) high-sulfur coal was selected to investigate the sulfur-fixation effect of copper oxide (CuO) on H₂S and SO₂ and its catalytic effect on the decomposition of thiophene by pyrolysis connected with gas chromatography (Py-GC) and XPS. The mechanisms of sulfur-fixation and thiophene decomposition catalyzed by CuO were investigated by density functional theory (DFT) calculations. After optimization, the stable adsorption configurations of thiophene, H₂S and SO₂ on different CuO (1 1 1) surfaces can be obtained. By Py-GC analysis, H₂S release of YQ coal significantly decreases after adding CuO, meanwhile Cu₂S obviously appears in XPS spectra, suggesting CuO possesses the strong sulfur fixation effect on H₂S. This is very consistent with calculated results about stable absorption of H₂S and its easier dissociated reactions whether on the perfect or enriched - oxygen surfaces. However, CuO possesses the weak ability for break SO₂ by GC analysis and DFT calculation. But the enriched oxygen can promote CuO to absorb and decompose SO₂. Thiophene is much easier theoretically to decompose under oxygen condition or on the enriched- oxygen CuO (1 1 1) than under Ar atmosphere. This is very consistent with the obvious increasing of thiophene content in XPS spectra of 12% CuO-YQ char and SO₂ concentration during different CuO-YQ char combustion. Thus, these experimental results are very in consistence with the DFT theoretical calculations in this study.