Abstract: The main reason of difficult to settling of coal slime is high content of clay minerals,finer particle size and formed into colloidal suspension,in which,the kaolinite is the main ingredients.The paper researched the influence of kaolinite on settlement of coal form two aspects of particle size and content of kaolinite in slime.The research result shows that the particle size of kaolinite has little effect on settlement of slime;the cation PAM is appropriate for settling of coal slime containing kaolinite,and with the increase of content of kaolinite,the adding amount of cation PAM is 2‰ to 3‰ is suitable.