The invention provides a semi-automatic transmission control device which comprises a gear-shifting control unit, a gear-shifting booster, a traveling computer, a servo motor, a gear-shifting handle, a mechanical control body part and a clutch pedal. The servo motor is used for replacing the gear-selecting function of a transmission, the gear-shifting booster is used for replacing the gear-shifting function of the transmission, and by means of the control unit integrated on a gear-shifting handle ball and a gear-shifting controller, the gear-shifting function can be achieved easily. The gear-shifting intensity is reduced by 95% or above. Compared with a common mechanical transmission control device, the device is easy to operate, small in arrangement space, high in transmission efficiency, excellent in gear-shifting hand feeling and capable of being compared favorably with that of a common family car. Compared with the AMT, the device is low in cost, the execution strategy is simple, the design is relatively simple, and few fault points are generated.