Abstract: The 10^# raw coal treated by Wuhushan Plant is complex in property and the clean coal product produced is high in sulfur content. Given the characteristics of the raw coal, a study is made on the effect of sulfur distribution of raw coal on washability of sulfur based on investigation and analysis of the sulfur distribution characteristics of raw coal. Study result indicates that: the 10^# raw coal is a high-sulfur coal and contains predominately pyrite sulfur which accounts for 77.17% of the total sulfur; along with the increase of size of test sample, the ash and sulfur tend to gradually increase, and when the particle size is larger than 25 mm, the ash and sulfur content rise rapidly up to 50.78% and over 5.06% respectively; the higher the density of coal sample, the higher the sulfur content, and when the density drops below 1.6 g/cm³, each size fraction of the raw coal sample shows no noticeable change in sulfur content, which varies within the range of 1.87%~3.13%, and when the density of coal exceeds 1.6 g/cm³, the various size fractions all show a significant increase in sulfur content with a highest level being up to 12.36%. It is also observed through the study that the sulfur content of clean coal can in no way be reduced to less than 1% by using conventional gravity separation method; and to further reduce the sulfur of clean coal, it is required to resort to in-depth separation of pyrite sulfur by using breaking liberation or chemical method.