The invention provides a mechanical single-rod gearbox gear-selecting-shifting control mechanism. The side surface of the gearbox is provided with a flexible shaft fixing support, the flexible shaft fixing support is provided with a gear-selecting flexible shaft connection clevis and a gear-shifting flexible shaft connection clevis correspondingly, the side surface of the gearbox is provided witha rotating arm fixing support, the Z-shaped rotating arm fixing support is provided with a rotating arm in a coordinated manner through a rotating shaft, the upper end of the rotating arm is connectedwith a gear-selecting flexible shaft, the gear-selecting flexible shaft is connected to the control mechanism in a driving cab through the gear-selecting flexible shaft connection clevis, the lower end of the rotating arm is connected with a connection rod, the connection rod is horizontally connected with an outer gear-shifting rocker arm, the lower end of the outer gear-shifting rocker arm is connected to the gear-shifting flexible shaft connection clevis through a gear-shifting flexible shaft and finally output to the control mechanism in the driving cab, and the upper end of the outer gear-shifting rocker arm is provided with a splined hole and is connected with a horizontal gear-shifting rod of the gearbox. The mechanical single-rod gearbox gear-selecting-shifting control mechanism has the advantages that the height of the control mechanism of the gearbox is reduced, in particular the mechanical single-rod gearbox gear-selecting-shifting control mechanism makes room for the installation of the driving cab and a carriage, about 110 mm is reduced on the basis of an original two-rod control, and the hand feeling is good.