Abstract: In order to reduce SO2 emission volume and to improve the sulfur fixed efficiency of the coal,the carbide slag and red mud were applied to be compound as the main sulfur fixative.A study on the sulfur fixed experiment was conducted under Ca 1 S substance amount ratio of 1.8 and experiment temperature of 1 000 °C.An orthog onal experiment of three factors and two levels was conducted with the selection of sulfur fixed additive A, additive C and fly ash B.The experiment results showed that whe n the adding quantity of compound additive individually was the additive A with 5%, additive C with 8% and fly ash B with 4% in the percentages of the main sulfur fixative,th e sulfur fixed effect was the best and sulfur fixed efficiency was 64.87%.Meanwhile ,the analysis with scanning electron microscope showed that the surface structure would be varied in different degree after the high temperature treatment of sulfur fixative added .A thermogravimetric analyzer was applied to investigate the compound additive af fected to the combustion features of the coal sample. Thermogravimetric curve of coal sample added with the compound sulfur fixative was the same to the raw coal basica lly.The ignition point was a lttle bit delay to the raw coal,but there was no big change.The combustion process would be two stage combustions,the second stage combusti on would be in a high temperature,the burnout temperature would be risen and the burnout time would be expended obviously.