Abstract: In order to solve the problems of high ash content of slime,difficult to control of the ash content of total clean coal and large loss of clean coal in Yonglong coal preparation plant,the TBS was added into coal slurry system to increase the coarse slime recovery rate,and the particle size of jigging middling has been crushed to less than 3 mm,and then primary and secondary separated by TBS. The renovation result in Yonglong coal preparation plant shows that the ash content of clean coal can be controlled in the required range,the clean coal yield has been increased by 5. 71 % and the economic benefit is outstanding.