A method for controlling a power-split gear shift device in a vehicle by providing an electric variator and a transmission with variable gear shift and connecting a drive motor to a traction drive of the vehicle. The electric variator has a compound gear train with at least one first and at least one second electric machine. The method also includes providing a controller for the electric machines for steplessly varying a gear shift of the compound gear train. Upon detection of an external power requirement by an electric consumer, a gear shift region of the transmission with variable gear shift is set to operate the first electric machine in a generator mode and to operate the second electric machine to compensate for an existing power deficit or a power excess relative to an external power demand.