A system for machining and positioning an automobile hub and a production line for intelligent cleaning and precision including upper and lower mounting plates connected vertically. At least three U-shaped blocks are fixed on a top surface of the upper plate. An L-shaped support is mounted between every two blocks including a screw-equipped ball head disposed thereon. The support is driven by a first driving apparatus to move along the upper mounting plate. A slidable chuck is disposed in each block, with a push rod assembly connected to the bottom. The assembly is driven by a second driving apparatus to move along the upper mounting plate with the chuck. Three wedges are circumferentially fixed on a top surface of the lower plate and are driven by a third driving apparatus to move along the lower plate. Inclined surfaces of the wedges are mated with bottoms of the push rod assemblies.