The invention provides a precise aerial alignment system and method a suspension bridge steel bridge. A fixing rack and a counterforce rack are respectively mounted on two steel beam alignment end topchords to be aligned; the fixing rack is connected with the counterforce rack through a pull rod; the pull rod is fastened by using a screw nut at a fixing rack end; an auxiliary screw nut is screwedat a counterforce rack end, sequentially penetrates through a box type pushing bracket, a jack and a pad plate and is screwed and fastened; two steel beams are mutually approached and aligned by using the jack through a traction pull rod; chain blocks are mounted on lugs on both sides of the top surface of a steel beam; each chain block is connected with an opposite lug on the other steel beam ina diagonal manner through a steel wire rope; and the steel wire ropes are constantly tightened in the alignment process to prevent wind loads. By adopting the system, precise aerial alignment of steel beams can be rapidly achieved by virtue of stroke controllability of the jack, transverse stability of a longitudinal cross-pulling device and effectiveness of a transverse wind resistant device, the hoisting time of steel beams is shortened, and the construction cost can be reduced.