Foldable portable fixed steel straight ladder

The utility model discloses a foldable portable fixed steel straight ladder which comprises two rows of guard beams which are vertically and correspondingly arranged, a plurality of ladder beams are transversely connected between the two rows of guard beams, each row of guard beams comprises a plurality of connecting beams which are sequentially and rotatably connected, the connecting beams in the two rows are in one-to-one correspondence, and the ladder beams are connected with the ladder beams in a one-to-one correspondence mode. A limiting beam is vertically fixed in the length direction of each connecting beam, limiting circular plates are arranged at the two ends of each connecting beam respectively, the limiting circular plates are vertically fixed to the limiting beams, and the limiting circular plates on every two adjacent connecting beams coincide with each other; a connecting rod capable of rotating around the axis of the connecting rod is connected between the two mutually overlapped limiting circu