Abstract: In order to study the influence of riffle on the separation effect of spiral chute,a experiment was carried out by laying riffles on the groove face of spiral chute and changing the angle between riffle and the diameter of chute,the change rules of the ash of clean coal,ash of tailings,clean coal yield and comprehensive efficiency of each size fraction was obtained.The results show that:comparing with free groove face,when the angle is positive,the ash of clean coal and clean coal yield of each size fraction both increase,and reach the maximum at 45°,the comprehensive efficiency of coarse fraction is highest at 60°,the comprehensive efficiency of fine fraction fall;when negative,for the coarse fraction,the ash of clean coal is lowest at -45°and the comprehensive efficiency is highest at 0°,for the fine fraction,ash of clean increase,comprehensive efficiency drop.