The invention provides a universal operating device for an overdrive gearbox and a use method thereof. The universal operating device comprises a gearbox gear selecting and shifting shaft, and a gear selecting and shifting rocker arm and a gear selecting and shifting block, which are arranged on the gearbox gear selecting and shifting shaft, wherein one end of the gearbox gear selecting and shifting shaft is separately in transmission fit with a gear selecting flexible shaft and a gear shifting flexible shaft through the gear selecting and shifting rocker arm, and the other end of the gearbox gear selecting and shifting shaft is in transmission fit with a gear shifting guide block through the gear selecting and shifting block; the gear selecting flexible shaft is in transmission fit with the gear selecting and shifting rocker arm through an overdrive gear switching device; and the overdrive gear switching device comprises a gear shifting fork, the upper end of the gear shifting fork is in transmission fit with the upper end of the gear selecting and shifting rocker arm, and the lower end of the gear shifting fork is in transmission fit with the lower end of the gear selecting and shifting rocker arm. In use, the transmission direction of the gear selecting and shifting shaft is changed by utilizing the translation of the rocker arm without changing the inner structure of the gearbox. Therefore, the design is simple in structure and low in manufacture cost, and can realize the gear order reverse shifting of the gearbox without changing the inner structure of the gearbox.