Focusing device and method for satellite remote sensing camera

The invention provides a focusing device and method for a satellite remote sensing camera. The focusing device comprises a focusing ring assembly and a motion transmission assembly, wherein the focusing ring assembly and the motion transmission assembly are used for enabling a camera lens focusing ring to conduct small-step-length planar motion. As the focusing ring assembly and the motion transmission assembly which can achieve small-step-length planar motion in orbit are adopted in cooperation with each other, accurate small-range focusing of the camera lens focusing ring is achieved; when the focal plane is out of focus because a satellite is influenced by temperature variation of a space environment, the focal distance of the remote sensing camera can be accurately adjusted through the focusing device, and then clear imaging of the satellite remote sensing camera is achieved. The focusing device has the advantages of being simple in structure, convenient to operate, high in focusing precision and the like, and the excessive focusing problem is avoided.