For the shortcomings of image acquisition device in the image matching aided navigation system, a criss cross rotatable varifocal mechanism driven by ultrasonic motor is developed. Firstly, an adjustable criss cross structure is adopted as supporting frame, which is suitable for two sets of sensors. Thus, the alternative work of multi sets of sensors can be realized, and the mechanis mcan be simplified, varifocal time can be shortened and varifocal accuracy c an be improved. Secondly, with the ultrasonic motor as driven source, the mech anism has many advantages, such as anti interference in electromagnetic, a high control accuracy of bare axis and self-locking when cutting off the electricit y . Lastly, this mechanism will be applied to the image matching aided navigation system, the system’s error will be eliminated in the process of obtaining image by using a closed loop control system, and the mechanism will cooperate with the image matching processing software to complete the tasks. The results indicate that, in different load conditions, this new varifocal mechanism runs half circle within 450 ms and stability accuracy of bare axis is less than 0.1°, w hich meet the requirements for the following image matching algorithm and is capable for the application in navigation system.