Gearbox of vehicle

The utility model provides a gearbox of a vehicle. The gearbox of the vehicle comprises a box shell unit, a power unit arranged on the box shell unit and a mechanism unit installed on the box shell unit. The box shell unit comprises a box body defining a first space and a second space. The box body is provided with a first hole wall defining a through hole, a first supporting piece arranged in the through hole, a second hole wall defining an open hole coaxially communicated with the through hole, and a second supporting piece arranged in the open hole. The power unit comprises a power source and an input shaft which is connected with the power source and is supported by the first supporting piece. The mechanism unit comprises a rotating shaft connected with the end of the input shaft, a clutch arranged on the rotating shaft in a sleeved mode and a plurality of gear-speed gears. The two opposite ends, close to and away from the input shaft, of the rotating shaft are supported by the first supporting piece and