The present invention provides a drive device for a middle-high voltage vacuum circuit breaker chassis, which comprises a drive motor (10), a clutch (11) and a drive chain wheel (12); the clutch (11) is installed on an output shaft of the drive motor (10), the drive chain wheel (12) is directly fixed with the clutch (11), and the drive chain wheel (12) is driven by the drive motor (10) through the clutch (11). The drive device further comprises a driven chain wheel (13) and a chain (14) or a belt, the driven chain wheel (13) is fitted over a lead screw (15) of the chassis; and the driven chain wheel (13) is driven by the drive chain wheel (12) through the chain (14) so as to drive the lead screw (15) to rotate together. The drive device further comprises a position locking device (39), which is insertable into a recess (37a-c) on the lead screw (15) to lock the chassis.