The invention discloses a floating seal air cooling device which solves the sealing problem that two sealing members need to keep a certain gap and mutually float. The floating seal air cooling device comprises an air channel (3), a lower annular tank (7), positioning pins (9), pressure springs (11), guide pipes (8), a reverse fastened upper annular tank (6), an air cooling cylinder (1), a plurality of elastic cushions (10) and a floating gap (5), the air channel (3) is formed in an air cooling device base (2), the lower annular tank (7) is fixedly formed in a circular outlet in the air channel (3) of the air cooling device base (2), the positioning pins (9) are arranged on the bottom face of the lower annular tank (7) at intervals, the pressure springs (11) are connected on the positioning pins (9) in a sleeving manner, the guide pipes (8) are connected on the pressure springs (11) in a sleeving manner, the upper annular tank (6) is formed in the top ends of the pressure springs (11), the air cooling cylinder (1) is fixedly arranged on the top face of the upper annular tank (6), the elastic cushions (10) are arranged among the guide pipes (8) and the upper annular tank (6), and the floating gap (5) is formed between the air cooling device base (2) and the air cooling cylinder (1). The floating seal air cooling device is simple in structure and easy to implement.