Adjustable fixing device for steel structure welding

The invention discloses an adjustable fixing device for steel structure welding, which comprises a middle connection adjusting beam part and two clamping frame parts which are positioned at two ends of the middle connection adjusting beam part and are symmetrically arranged, each clamping frame part comprises a supporting plate and two clamping plates positioned on one side of the supporting plate, and the middle connection adjusting beam part comprises a bidirectional telescopic base beam; the action ends of the two ends of the two-way telescopic base beam are connected with the other sides of the supporting plates on the two frame clamping parts in an up-down rotating mode respectively, and the middle connection adjusting beam part comprises a synchronous transmission mechanism. According to the device, by arranging the two-way telescopic base beam, the middle connecting sliding frame, the adjusting mechanism and the buffer telescopic rod, when the device lifts the middle connecting sliding frame through a