The invention relates to a two-dimensional ultrasonic vibration polishing device and a two-dimensional ultrasonic vibration polishing method, and belongs to the technical field of machine manufacturing. A two-dimensional ultrasonic vibration polishing tool is fastened to the z-axis of a machine tool by screws; a workpiece fixture is fastened to the x-axis of the machine tool by the screws; and the x-axis, the y-axis and the z-axis of the machine tool are fixedly connected with a machine tool main body after debugging. The two-dimensional ultrasonic vibration polishing device provides elliptical vibration in a polishing tangent plane, vibration signals of an x-direction ultrasonic vibrator and a y-direction ultrasonic vibrator are coupled to form two-dimensional vibration at a pivoting joint, and are output to a polishing head, the polishing head acquires a perfect instantaneous random motion track in a processing area, and motion composited by the vibration is polishing primary motion, so that a polishing force can be controlled to be stable on the premise that no polishing head rotates; the polishing head has high profile modeling capability, so that various complicated curved surfaces can be processed; deterministic polishing is realized; stable and uniform removal of a polishing material is realized; and high-efficiency and high-quality polishing can be realized simply by controlling the polishing force.