The invention discloses a dynamic detector of train wheels and relative detecting method, which can improve the driving safety. Said detector comprises a on-site controller, a remote-controller, and a on-site detector, wherein, the on-site detector is controlled by the on-site controller to output the detecting result, which via the remote transmission channel is transmitted to the remote controller to be processed; the remote-controller comprises a background wheel dynamic detecting software, to control the open, detecting, image picking, automatic wheel size detecting, accident recognize, automatic storage, displaying, and printing; the on-site controller controls the on-site detector to detect and keep communication with the remote-controller. The invention can avoid contact train, with high automation and detecting accuracy, while it can realize unattended management.