Vehicle center line calibration method and system

The invention relates to a calibration system and a calibration method for a vehicle center line. The calibration system for the vehicle center line comprises a vehicle datum reference device, a vehicle attitude detection device, a calibration device and a data processor, wherein the data processor is used for obtaining a vehicle deviation angle according to a numerical value measured by a laser scanning ranging radar; the vehicle datum reference device comprises a front reference device and a rear reference device which are arranged in front and rear license plate frames of a to-be-calibrated vehicle; the center connecting line of the metal balls of the front reference device and the rear reference device and the datum center line Y0 of the vehicle are located on the same vertical plane. The vehicle posture detection device comprises a body support, a two-axis sliding table which is installed on the body support and can slide in the X-axis direction and the Y-axis direction of the body support, an electric t