A distributed air floatation three-phase separator mainly comprises a separating mechanism of the separator and a distributed air floatation separating mechanism. Distributed air floatation technology is introduced to the oil, gas and water three-phase separator to be integrated with the structural design of the three-phase separator to form reasonable layout, gas separated out by the three-phase separator is pressurized by a compressor of the distributed air floatation separating mechanism, then the gas is released through a micropore aeration tube so as to deeply separate crude oil, and three-phase separating effect is improved. The distributed air floatation three-phase separator is particularly suitable for pre-separation of crude oil and thickened oil in enhanced oil recovery, meets the requirement on electrical dewatering, and leads exportation crude oil to reach the target that water content in crude oil is 1%.