The vehicle-mounted intelligent track inspection system consists of three major subsystems: under-vehicle track defect image acquisition and positioning sensing system, in-vehicle intelligent inspection information processing and management system, ground vehicle section server and system terminal. The system images the track bed area in full section in high definition during train operation, and then detects defects in the track image to discover track defects (such as rail cracks and broken rails; rail sleepers and rail plates cracks; rail sleepers falling blocks; rail fasteners broken and missing; foreign objects invading the bed space) in time. Then the track defect picture, defect location and other information will be sent to the ground server through the vehicle wireless network or 4G/5G mobile communication, and the second identification and processing of the inspection sink knot data will be pushed to the terminal computer monitoring interface display in real time, so that the ground maintenance center personnel timely evaluation and processing of defects, and improve the efficiency of track line inspection.