A power transmission system for a vehicle and a vehicle including the same are provided. The power transmission system includes: an engine unit; a plurality of input shafts, in which the engine unit is configured to selectively engage with one of the input shafts when the engine unit transmits power to the input shafts; a plurality of driving gears with one driving gear disposed on one input shaft; an output shaft configured to transfer the power from the input shafts; one or more linked gears rotatable at a different speed relative to the output shaft, in which the linked gears include a plurality of gear parts, the gear parts being configured to mesh with the driving gears on the input shafts; an output unit coupled on the output shaft and configured to transmit the power to front wheels of the vehicle; a clutch disposed on the output shaft and configured to selectively engage with the linked gear and the output unit so as to drive one or more wheels of the vehicle via the power output by the output unit; and a first motor generator configured to couple with one of the input shaft and the output shaft for power transmission.