According to the gravity difference of the mineral separation, the spiral chute is to used to the inclined flow method, slurry is fed into a chute with a small dip Angle (3 to 4 degrees, no more than 6 degrees), and the particles are stratified according to density under the combined action of water impulse, gravity, centrifugal force and friction. Because the velocity distribution of water flow in the trough is large in the upper layer and small in the lower layer, and the dense ore particles are concentrated in the lower layer, the water impulse force and the greater friction force at the bottom of the trough move forward slowly along the bottom.The less dense particles are concentrated in the upper layer and carried by the current, which flows out of the trough at a faster rate.Then, two products with different densities, concentrate and tailing, can be obtained by layer.