A power transmission system for a vehicle includes: an engine; input shafts, at least one of which configured to selectively engage with the engine, each of the input shafts being provided with a shift driving gear thereon; output shafts, each of the output shafts being provided with a shift driven gear configured to mesh with a corresponding shift driving gear; a motor power shaft configured to rotate together with one of the output shafts; and a first motor generator configured to rotate together with the motor power shaft, wherein when the motor power shaft is rotated together with one of the output shafts, the first motor generator is configured to generate electric power utilizing at least parts of power generated by the engine while the vehicle in a running state or a parking state. A vehicle including the power transmission system is also provided.