Disassembling and assembling tool

A dismounting tool comprises a rod piece unit, a connector component and a fixing piece set. The rod piece unit comprises a mounting base. The mounting seat is provided with a base part and two support arms which are arranged at an interval; the base portion has a first engaging portion. Each support arm is provided with a through hole which extends along the axis and penetrates through two opposite surfaces. The connector component can be rotationally arranged on the mounting seat, and the connector component comprises a mounting head which can be rotationally arranged on the mounting seat. The mounting head is provided with a body and a second joint part used for being jointed with the first joint part. The body is provided with a through hole. The fixing piece set comprises fixing pieces installed in the penetrating holes and the through holes. The stress is dispersed through the design that the first connecting part is connected with the second connecting part, the fixing piece or the supporting arm is pr