The pulsing curve of the traditional jig is sinusoidal waveform, the up and down speed of water flow and acting time produced by the movement of membrane are almost same, so it is unfavorable to loose of jig bed and layering of minerals based on special gravity, and thus affect separation ability and recovery rate. Saw-tooth wave is an energy economy gravity equipment that is developed and improved from traditional jig on the basis theory of jig bed layering. Its jigging pulsating curve is similar to saw-tooth wave, which makes the up speed of water flow quicker than down speed of water flow, so it can improve looseness of jig bed and reduce suction action, which can lead to fully settlement of heavy particles in slurry, it highly improves separation ability and recovery rate. Stroke and frequency of stroke are adjustable.