A removable cantilever gantry crane container checking apparatus relates to a radiation scan imaging check technical field, which comprises a movably scan equipment formed with a radiation source, a scanning frame formed by detectors and a remote control apparatus. The utility model had a structural character that the radiation source or an equipment storehouse equipped with the radiation source is connected with an L-shaped cantilever structure to form a gantry frame. Rollers which are capable of back and forth motion on an orbit are equipped under the radiation or the equipment storehouse equipped with the radiation source and the rollers are controlled by a drive device. The detectors are positioned in a beam and an upright beam of a gantry frame cantilever structure and radials of the radiation source are just faced with various ranges of detectors in the gantry frame cantilever structure. Detected container trucks are capable of passing through a door case formed by the gantry frame. The utility model is designed into a cantilever structure to make the checking system has the advantages of stable movement, excellent imaging quality and high reliability or the like.