An imaging system configured to automatically detect a patient's body profile and to position the patient. The imaging system includes a scan support member configured to support a scan object, a processing device; and an identification device electrically connected to the processing device. The scan support member includes a machine identifiable code representing a distance from a position of the machine identifiable code to one end of the scan support member. The identification device is configured to identify the machine identifiable code, to decode the distance represented by the machine identifiable code and to send the distance represented by the machine identifiable code to the processing device. The processing device determines a distance from an interested location of the scan object to a scanning plane of the imaging system according to the distance represented by the machine identifiable code.