The invention relates to a high-efficiency air flotation device for sewage treatment, which includes an air flotation tank, an air flotation machine, an air inlet pipe, a water inlet pipe, a water outlet pipe, a controller, a top plate, a lifting mechanism, a first motor, a rotating shaft, and two filtering mechanisms and a number of deceleration mechanisms, the filter mechanism includes a filter screen, a flat plate and a shrinking assembly, the shrinking assembly includes a second motor and two shrinking units, the shrinking unit includes a bearing, a transmission shaft, a reel and a pull wire, the deceleration mechanism includes several deceleration assemblies, the deceleration assembly Including horizontal plates and several deceleration units, the high-efficiency air flotation device for sewage treatment reduces the rising speed of bubbles in water through the deceleration mechanism, so that the bubbles have enough time to contact and drive the solid particles in the sewage to float up, so as to achieve efficient purification Treatment, not only that, the filter mechanism makes the scum stay on the surface of the filter screen during drainage, which is convenient for people to clean up the scum and achieve the purpose of solid-liquid separation, thereby improving the practicability of the equipment.