The utility model relates to a cross beam connecting rod shaft dismounting device which comprises a left mounting limiting plate and a right mounting limiting plate, and the left mounting limiting plate and the right mounting limiting plate are detachably connected through a plurality of sets of middle adjustable connecting pieces. A dismounting mechanism is arranged on the left mounting limitingplate, a set of dismounting grooves are machined in the corresponding positions of the right mounting limiting plate, and the inner side end face of the left mounting limiting plate and the inner sideend face of the right mounting limiting plate are each provided with a set of electromagnetic attraction device. According to the utility model, the left mounting limiting plate and the right mounting limiting plate are arranged; the left mounting limiting plate and the right mounting limiting plate are respectively arranged at the two ends of the cross beam; cross beams of different sizes are matched through self-adjustment of the middle adjustable connecting piece, the lead screw is driven to move forwards through forward rotation of a driving motor in the disassembling mechanism till the lead screw is connected with the connecting rod shaft in a matched mode, the driving motor rotates reversely, the disassembling lead screw is driven to retreat, meanwhile, the connecting rod shaft fixing bolt is driven to be disassembled, and disassembling work of the connecting rod shaft is completed.