The utility model relates to a disassembling and assembling tool for a pressure gauge dial. Mounting rack, the mounting frame is provided with two clamping arms which are oppositely arranged at intervals in the left-right direction and used for clamping the dial plate in a matched mode. The two clamping arms are respectively provided with an insertion part which faces the opposite inner sides of the two clamping arms and is used for being inserted into a groove in the outer side of the dial plate. At least one of the two clamping arms is a movable clamping arm capable of moving in a reciprocating mode in the left-right direction, a driving screw extending in the left-right direction and used for driving the movable clamping arm to move in a reciprocating mode is arranged on the installation frame, and a threaded hole matched with the driving screw in a spiral transmission mode is formed in the movable clamping arm. And the two clamping arms are matched to clamp the dial plate, and themounting frame is rotated, so that the dial plate can be conveniently disassembled and assembled. Due to the fact that at least one of the two clamping arms is the movable clamping arm, the screw rodcan be driven to rotate to adjust the position of the movable clamping arm, the clamping requirements of dial plates of different sizes are met, and the universality of the disassembling and assembling tool is effectively improved.