Abstract: In order to improve the desulfuration efficiency of high- sulfur coal in flotation process,taking a high- sulfur slime in Xinyu coal preparation plant as research object,the size composition and sulfur forms were analyzed. The influence of coal slurry mass concentration,collector,frother and depressor types and contents on high- sulfur coal flotation was investigated. The results showed that the sulfur content in slime was 3. 57%,the pyrite content in slime was up to 2. 18% which was difficult to be released,so the desulfuration efficiency was low. When the coal slurry mass concentration was 80 g / L,the dosage of Nalco oil,octanol and thioglycolic acid was 200 g / t,100 g / t,400 g / t,the flotation achieved the best effects. The sulfur in clean coal was 2. 35%,the recovery of combustible materials was 69. 23%,the desulfuration efficiency reached a maximum value of 24. 76%.