The system can accurately and efficiently display the images of the vehicle chassis, roof and other parts, and compare it with the database chassis and other images, and can automatically identify foreign objects and automatically voice alarms. The scanning imaging speed is fast, and it can be scanned in different ways under different complex environmental conditions. The vehicle chassis image can be clearly identified with a linear 0.5mm object size, and all the dangerous goods hidden in the vehicle chassis can be seen at a glance.