Abstract: The high sulfur coal Hunan Meitanba was used as the experiment sample. The carbide slag was added based on the Ca/S mol ratio of 1.5. K2CＯ3, Al2O3, Fe2O3 and rare earth minerals ( weight of rare earth oxides above 58%) about 1.0% were added in the coal respectively. The promotion effects of the additives and catalytic mechanism on carbide slag sulfur capture were studied. The results show that 4 additives have good promotion effects on sulfur capture by carbide slag between 800 ℃ and 1 100 ℃. Adding K2CＯ3 has the best sulfur capture result at about 1 100 ℃. Decomposition temperature of carbide slag and utilization efficiency of Ca are improved to increase sulfur capture ratio when Al2O3 is added. Fe2O3 has a good effect on sulfur capture, and the effect weakens with increasing temperature. Rare earth element has particular electronic shell structure which makes especial catalysis impact on sulfur capture. Al2O3 is the best among the 4 additives and it makes sulfur capture ratio reach above 70%, and rare earth minerals is the second.