A vehicle pulling device, a system for passing a vehicle in two modes, and an inspection system for scanning a vehicle by radiation are disclosed. The vehicle pulling device comprises a movable chassis disposed in a passage for a vehicle and being movable in a first direction; and a support beam disposed to the movable chassis and being rotatable between a first position and a second position. In the first position, the support beam is located substantially in a second direction substantially perpendicular to the first direction, such that wheels of the vehicle are interacted with the support beam of the vehicle pulling device so that the vehicle is pulled to pass through the passage; and in the second position, the support beam is located substantially parallel to the first direction such that the wheels of the vehicle are not interacted with the support beam of the vehicle pulling device so that the vehicle travels by itself to pass through the passage. Therefore, when the vehicle does not need to be pulled, the support beam is rotated to the second position, and the vehicle travels by itself to pass through the passage. When the support beam is rotated to the first position, the vehicle pulling device can pull the vehicle to pass through the passage.