The invention discloses a mobile vehicle inspection system, comprising a mobile device, a drive device which drives the mobile device to move during scan checking, a ray source disposed on the mobile device and used for irradiating rays, and a slope benching device which is used for increasing the height of the inspected vehicle to ground and comprises a first slope benching section and a second slope benching section, wherein each of the first and second slope benching sections respectively comprises a middle horizontal section, two transition sections detachably connected to two ends of the middle horizontal section respectively, and two inclining sections detachably connected to the two transition sections respectively. The vertical detector beam of the mobile vehicle checking system disclosed by the invention does not need to be folded when the vehicle runs or scan checking is performed, and the inspection system has the characteristics of simple structure, convenience in processing and debugging, wide scanning range, light weight of the vehicle body and low manufacturing cost.