In order to improve the driving ability and working efficiency of ultrasonic motor， a rectangular plate type patch four-leg linear ultrasonic motor is designed. The motor stator consists of phosphor bronze and eight piezoelectric ceramic sheets， and the four driving feet are distributed at four corners of the rectangular plate. The motor uses the in-plane first-order longitudinal vibration of the rectangular plate and the out-of-plane anti-symmetric bending vibration to superimpose each other to form an elliptical motion trajectory at the driving foot. The modal harmonic response of the motor through finite element software is calculated to analyze and verify the motor working principle. The motor is tested when the excitation voltage is 200 V and the excitation frequency is 25 810 Hz. The maximum no-load speed of the motor is 130 mm/s when the pre-pressure is 10 N， and the maximum load of the motor is 3.5 N when the pre-pressure is 12 N. The results show that the motor has good output performance.