The invention relates to a multi-stage gear anti-backlash transmission device for backup of a low-energy consumption redundant motor of a south-polar telescope. The device is provided with a driving motor and a transmission gear. The device is characterized in that a final stage rack wheel 1 is engaged to a first final stage pinion 2-1, the first final stage pinion 2-1 and a first initial stage rack wheel 3-1 are coaxially mounted, the first initial stage rack wheel 3-1 is engaged to a first initial stage pinion 5-1, the first initial stage pinion 5-1 is engaged to a closed loop transitional gear 7, the closed loop transitional gear 7 is engaged to a second initial stage pinion 5-2, the second initial stage pinion 5-2 is engaged to a second initial stage rack wheel 3-2, the second initial stage rack wheel 3-2 and a second final stage pinion 2-2 are coaxially mounted, and the second final stage pinion 2-2 is engaged to a final stage rack wheel 1 to form a closed transmission chain. According to the device provided by the invention, anti-backlash drive by a single motor is realized, and the device is simple to control, low in energy consumption and low in cost. Redundant backups of the driving motor and a driving torque can be further realized, and the reliability of the device in an extreme environment of south pole is improved.