This paper presents an analysis model of temperature effects on resona nt frequencies of traveling wave ultrasonic motors in which the ringform stato r is equivalent to a composite beam model. Considering the temperature effects on pizeomaterial and metal base of the stator, a temperature coefficient was ado p ted. The variation of resonant frequency due to the alteration temperature was p articularly researched. An experimental system was built in which the motor’s c haracteristics and the friction material dependence on motor’s stability were t ested in cryogenic conditions. The influence of temperature on friction interfac e was also studied by comparing the material’s surface appearances. The results show that the performance of traveling wave ultrasonic motor in lowtemperatur e degrades, and it is even worse in lower cryogenic conditions.