A lens seated device for driving a single lens reflex (SLR) camera zooming comprises an adapting ring, a big gear, a small gear, a motor and a chassis. The chassis sustains the SLR camera, the adapting ring, the big gear, the small gear and the motor. The adapting ring clinches around the lens of the SLR camera and is seated and fixed on the big gear. The motor is used for driving and directly rotating the small gear, and then the small gear will drive to rotate the big gear. The rotation of the big gear will drive and rotate the adapting ring accordingly, and thereby drive the lens of the SLR camera for zooming.