A new kind of ultrasonic machining method named ultrasonic machining aided tool rotation is proposed for sintered NdFeB permanent magnet. In the process abrasive slurry enters the machining area through holes in the rotary tool which can assure the grains easily enter the machining surface slurry. Its machining mechanisms are studied and material removal model is developed. Experimental research was carried out on self-made equipment. Experimental results were accordance with the developed model. It is proved that this new kind of ultrasonic machining technology is suitable to machine deep hole for sintered NdFeB material.