Due to the influence of mechanical environment, large range temperature change and atmospheric pressure, the space multispectral camera has a certain amount of defocus in the optical imaging system. In order to improve the imaging quality of the multispectral camera, if the traditional CAM focusing mechanism is adopted, it is difficult to meet the requirements of high precision focusing for fast response due to its disadvantages such as large volume, poor efficiency and low precision. Therefore, a new focusing mechanism is designed in this paper, which is composed of rhomboid amplifier large piezoelectric ceramic actuator, flexible hinge support structure and high-precision capacitance sensor. The mechanism drives the flexible support guide structure of the parallelogram by means of a rhomboid amplifier large PZT actuator with three points distributed uniformly and symmetrically at 120°, so that the lens base can move in a straight line along the Z direction. The high precision capacitance sensor is used as the feedback element to ensure the focusing accuracy of the mechanism reaches nanometer level. The test results show that the focusing range of this mechanism is ±21.91um, the focusing speed is 438um/s, the focusing precision is 50nm and the tilt error is 1". © 2021 SPIE