The invention discloses a load matching device for ultrasonic machining. The load matching device comprises an air flotation workbench, an air flotation guide rail air supply system of the air flotation workbench, a pneumatic control system and a force monitoring system, wherein the air flotation workbench comprises a guide rail-cylinder; the bottom of the guide rail-cylinder is fixedly connectedwith the top of a base; an inner guide sleeve is sleeved outside the guide rail-cylinder; the inner wall of a central through hole of the inner guide sleeve is in clearance fit with the outer wall ofthe guide rail-cylinder to form an air film clearance; an outer guide sleeve is sleeved outside the inner guide sleeve; a supporting plate and a workbench top are sequentially fixedly connected at the top of the outer guide sleeve; the outer guide sleeve is provided with a plurality of air supply ports communicated with the air flotation guide rail air supply system of the air flotation workbenchalong the circumferential direction; and the base is provided with an air inlet passage connected with the pneumatic control system. The device realizes machine tool accessories and universality of an ultrasonic machining load matching system, and realizes accurate force control in the ultrasonic machining process.