The invention discloses a testing machine for testing a crane scale and a method for disassembling and assembling a weight thereof. The testing machine for testing a crane scale comprises a position adjustment control device, a rack, a weight, a weight drive mechanism, a weight swing mechanism, a suspender and an anti-swing mechanism, wherein the weight swing mechanism comprises a weight swing mechanism shell, a motor No.3, a stop dog, a worm, a worm gear and a weight swing mechanism driving part, the worm and the weight swing mechanism driving part are installed in the weight swing mechanismshell and are in rotating connection, the worm gear is sleeved on the weight swing mechanism driving part and is fixedly connected with the weight swing mechanism driving part, and the worm and the worm gear are engaged with each other, the output shaft of the motor No.3 fixed on the weight swing mechanism shell is fixedly connected with the worm, the stop dog is installed in a through groove of the weight swing mechanism driving part, the weight swing mechanism is installed at the center of a middle cross beam of the rack, the weight swing mechanism driving part is sleeved on the suspender, and a through hole on the weight swing mechanism driving part is in clearance fit with the suspender. The invention also provides a method for disassembling and assembling the weight in the testing machine.