An on-vehicle three-dimensional video system is provided for a vehicle and a method is provided for monitoring a surrounding environment of a vehicle. The on-vehicle three-dimensional video system includes, but is not limited to cameras, a display screen, a control module, and a power supply device. The cameras are provided in pairs for filming the surrounding environment of the vehicle from different angles, and the display screen is able to bring about a three-dimensional video effect according to pairs of video signals from the cameras. With the on-vehicle three-dimensional video system, a realistic three-dimensional output of the surrounding environment of the vehicle is realized on the display screen so that the driver can clearly know about the precise relative position of a corresponding portion of the vehicle with respect to the surrounding environment.