In order to research the levitation capability of a ultrasonic bearing,a bidirectional ultrasonic bearing which levitates and supports a shaft in axial and radial directions respectively was introduced,and the max rotation speed of the shaft was measured.The generation mechanism of the ultrasonic radiation pressure from this kind of bearing and the working principle of the ultrasonic bearing were analyzed,then,a bidirectional support ultrasonic bearing was designed,and the max rotation speeds of the shaft with different levitation clearances were measured.The results indicate that when the shaft weigh is 85.5 g and the levitation clearance is 8.53 μm,the max rotation speed could be 8 946 r/min.The results also show that the bidirectional support ultrasonic bearing could support the shaft in a levitation state,and the smaller the levitation clearance and the greater the bracing stiffness of the bearing support are,the better the stability and the higher the rotation speed of the shaft are.