The invention relates to a protrudent toothed belt groove longitudinal and bending mode conversion dual-rotor ultrasonic motor, which belongs to the technical field of design of ultrasonic micro-motors. The dual-rotor ultrasonic motor comprises a first rotor, a second rotor, a stator, a rotary shaft, a chassis and a spiral tube. The first rotor, the spiral tube and the second rotor are sequentially sleeved on the rotary shaft from top to bottom and then arranged on the chassis. The stator is screwed on the spiral tube, and the stator is composed of a first stator cap, a first piezoelectric plate, a second piezoelectric plate and a second stator cap by sequential overlapping. A nut imposes pre-pressure on the first rotor and the second rotor through a spring. The ultrasonic motor adopts the dual-rotor structure, eliminates a bearing, has dual-end output and can rotate in single direction; furthermore, the torque is great, and the output torque can be more than 30 percent. The ultrasonic motor can be widely applied in industrial, defense and medical equipment as a driving source. If the high and low temperature resistant piezoelectric plates are used in the ultrasonic motor, then the ultrasonic motor can be applied in high and low temperature extreme environments.