The invention provides a centroid dynamic control device and method for a large-zoom ratio variable-focal length sensor. The device comprises a slide rail, a fixing bracket, a screw rod, a motor, a counterweight unit and an external controller; the slide rail is fixed on a sensor body; and the direction of the slide rail is parallel to the direction of the optical axis of the sensor; the fixing bracket is fixed on the sensor body; a threaded hole parallel to the direction of the optical axis of the sensor is formed in the fixing bracket; the screw rod is installed in the threaded hole of the fixing bracket; when rotating, the screw rod can move axially; one end of the screw rod is coaxially and fixedly connected with the output shaft of the motor, and the other end of the screw rod is fixedly connected with the counterweight unit; the motor is mounted on the slide rail and can slide on the slide rail; and the external controller can collect the position information of the motor on theslide rail and control the rotation and direction of the motor. When the large-zoom ratio variable-focal length sensor is in a focal length-varying state, the motor drives the screw rod to rotate, thecounterweight unit moves, and so that centroid dynamic control compensation is performed for the sensor. The device of the invention has the advantages of simple structure, high portability, easinessin realization and the like.