The invention relates to a train scanning system, comprising a train speed measuring device used for obtaining the current running speed of the train, and a line scanning camera fixedly arranged on the circumference of the running path of the train and capable of continuously acquiring images of the passing train to continuously obtain the longitudinal images of the train, wherein the interval of acquiring images by the line scanning camera is controlled though receiving the running speed of the train acquired by the train speed measuring device so that the images continuously acquired by the line scanning camera can be split jointed to be an integral image passing the line scanning camera part transversely. The system controls spacing interval of acquiring image by the line scanning camera through adopting the train speed so that the line scanning camera can continuously obtain the images of the train in various sections which are split jointed to an integral train image after arranged in sequence, and has clear images.