The utility model discloses a square round compressed air cooling spiral steel pipe which comprises a spiral pipe and connecting pipes arranged at the two ends, wherein the spiral pipe is in a spiral rectangle with a circular bead, and is formed by winding the common steel pipe in a spiral way; and the connecting pipes are straight. The square round compressed air cooling spiral steel pipe is smaller in occupied installation space, more beneficial to being installed and fixed on a vehicle and high in batch assembly efficiency when the vehicle compressed air cooling performance is met, thus solving the problems that the round spiral pipe is large in occupied space, hard to fix and the like, ensuring that a compressed air supply system is more reasonable and improving the reliability and the safety of the whole vehicle.