The invention relates to the field of assembly tools, in particular to a screw and bolt disassembling device and an application method thereof. The screw and bolt disassembling device comprises a main body, three gripper jaws, a driving device and a handle; the gripper jaws are slidably arranged in the main body; the sliding direction of the gripper jaws is the same as the diameter direction of the main body; the three gripper jaws are uniformly arranged with the axis of the main body as the center; the driving device is connected with the three gripper jaws and can synchronously drive the three gripper jaws to move; and the handle is arranged at one end of the main body. According to the application method, after the gripper jaws are synchronously adjusted to be spaced by the appropriate distance by the driving device, the handle is rotated to drive the main body to turn, and further, the gripper jaws are driven to rotate to disassemble or assemble screws. According to the screw and bolt disassembling device and the application method thereof, the structure is simple, convenience is achieved, three faces of the device are in contact with the screws, and the contact area between the screws and the screw and bolt disassembling device is greatly increased, so that contact between the screw and bolt disassembling device and the screws is more stable, force transferring is ensured, and clamping force is guaranteed.