The invention discloses a steel cord twisting and untwisting device. The steel cord twisting and untwisting device comprises an unwinding device, a twister, a torsional limiting device, an untwister, a winding device and a cord passing wheel, wherein the torsional limiting device is arranged between the twister and the untwister; a steel cord sequentially passes through an I-shaped wheel of the unwinding device, the twister, the torsional limiting device, the untwister, an I-shaped wheel of the winding device and the cord passing wheel arranged between the I-shaped wheels. By applying torsion to the cord, tension stress or pressure stress on the surface of the cord is changed into torsional shear stress, so that the stress on the surface of the cord is balanced, and the aim of straightening the cord is achieved; by applying reverse torsion to the cord, the residual torsion of the cord is eliminated, the cord which is produced and manufactured has excellent strength, toughness and anti-fatigue performances and is high in straightness and appropriate in residual torsion, the production requirements on a rubber cord fabric are met, and the cord is applied to tire belted layers.