The invention discloses a grinding wheel automatic assembly and disassembly device of a heavy numerical control roll grinder. The upper side of a ferrule of a hanger is fixedly connected with a lifting block by a tension rod in a rotating way; the ferrule is sleeved outside one end of a grinding wheel chuck plate; a main piston rod of a main oil cylinder on the end part of one side of the ferrulecan push a pressure block at one end of the grinding wheel chuck plate to move along an axial direction; an auxiliary piston rod of an auxiliary oil cylinder on the hanger can be just accommodated inan annular positioning groove on the radial outer sidewall of the grinding wheel chuck plate; the grinding wheel chute plate is sleeved outside a conical head of a main shaft of the grinder; and a handle of the grinding wheel chuck plate is detachably connected with a blind rivet at one end of the conical head of the main shaft of the grinder in a buckling way. The grinding wheel automatic assembly and disassembly device controls the assembly and the disassembly of the hanger and the grinding wheel chuck plate and the assembly and the disassembly of the grinding wheel chuck plate and the conical head of the main shaft of the grinder by controlling the main and auxiliary oil cylinders on the hanger so as to automatically disassemble and lifting-assemble a grinding wheel easily and conveniently, and has the characteristics of simple structure, flexible, simple and convenient operation, and time and labor saving.