Desulfurization and denitrogenation were systematically investigated by analyzing the chars and tars from pyrolysis of high sulfur Chinese Yanzhou bituminous coal with coke-oven gas (COG) at different operating conditions. The results were also compared with pyrolysis of coal under synthesis gas (SG), H-2 and N-2. It is found that desulfurization and denitrogenation in coal pyrolysis with COG, SG and H-2 are about 20% and 10-20% higher than those under N-2, respectively. At the same hydrogen partial pressure. desulfurization under COG (5 MPa) is about 4.5% higher than that under H-2 (3 MPa), while the denitrogenation is about 3.5% lower.