The specific gravity air separator is mainly used for the process of separating light and heavy objects in the garbage sorting process. The specific gravity separator is a separation and sorting equipment according to different density of materials, different particle sizes or different shapes of the same material. This machine makes the materials entering the machine pass through the suction and buoyancy force of the wind, and has effect on the difference of the suction and buoyancy force of different specific gravity and different granular materials, as well as the gravity and other aspects of the materials, so as to separate the materials with different specific gravity from the materials with the same particle size and shape through specific gravity air separation. The flaky materials with small specific gravity, small particle size or large wind receiving area sucked by the wind are discharged from the machine after being collected by the collector and dust collector. The materials with larger weight and the same kind of materials that are less affected by the wind are discharged from the other end of the machine.