Auxiliary straightening device used during H-shaped steel welding and using method thereof

The invention relates to an auxiliary straightening device used during H-shaped steel welding and a using method thereof. The device comprises a supporting base, top pressing mechanisms, bidirectionalpressing mechanisms, an arc striking traction plate and a traction mechanism, wherein H-shaped steel is arranged on a bottom plate of the supporting base; a plurality of sets of top pressing mechanisms are arranged on the top of the supporting base; top pressing rollers in the top pressing mechanisms are pressed on the top of an upper flange plate of the H-shaped steel; a plurality of sets of bidirectional pressing mechanisms are arranged in the supporting base; two cylinder rods of a bidirectional hydraulic cylinder in each bidirectional pressing mechanism vertically extend upwards and downwards correspondingly; the cylinder rods extending upwards are connected with upper pressing rollers; the upper pressing rollers are pressed on the bottom of the upper flange plate of the H-shaped steel; the cylinder rods exte