Provided are a system and method for measuring a vehicle gap or step, where a vehicle body to which a hood, a door, and a trunk lid are assembled is seated on a carrier and moved along transfer lines. The system may be installed over the transfer lines and may include one or more door regulating units attached between the vehicle body and the door, upper rails in both sides above a workplace corresponding to the transfer lines, a moving frame movable below the upper rails, a forward/backward moving unit above the moving frame, a horizontal moving unit to move installation frames, a vertical moving unit in the installation frames to reciprocally move a sliding plate upwardly and downwardly, a measurement module movable and rotatable to measure the gap or the step, and an electronic tag on a roof of the vehicle body.