Rotating disc type machining center and workpiece machining method

The invention discloses a rotating disc type machining center and a workpiece machining method, and belongs to the technical field of machine tool machining. The rotating disc type machining center comprises a base, a rotating table, a fourth shaft and a rotating mechanism; the rotating table is rotatably arranged on the base; the fourth shaft is arranged on the rotating table; the rotating mechanism comprises a motor, a lower spline shaft, a spline sleeve, an upper spline shaft and a lifting assembly, the motor is arranged on the base, the lower spline shaft is connected with the motor, the spline sleeve is arranged on the lower spline shaft in a liftable mode, the upper spline shaft is connected with the fourth shaft and can drive the fourth shaft to rotate, and the lifting assembly is connected with the spline sleeve. The lifting assembly drives the spline housing to ascend so that the spline housing can be connected with the upper spline shaft, or the lifting assembly drives the spline housing to descend