The invention discloses a device and a method for measuring the
diameter of a dense
pipe bundle and the thickness of an
oxide film on site. The device comprises a plurality of rod
diameter measurement units and a plurality of
oxide film thickness measurement unit which are mounted on a measurement rack, wherein the rod
diameter measurement units are all arranged in the same horizontal plane; the
oxide film thickness measurement units are all arranged in the same horizontal plane; a channel, through which a sample supply
pipe passes, is arranged inside each of each rod
diameter measurement unit and each oxide film thickness measurement unit; the channel of each rod
diameter measurement unit is correspondingly coaxial with the channel of each oxide film thickness measurement unit. By classification of the dense
pipe bundle, the device can directly and precisely measure the diameter of the dense pipe bundle and the thickness of the oxide film at any position in the whole
stroke on the site; in the measurement process, direct contact with a
human body is avoided; a sensor is configured to measure tiny changes of the diameter and the thickness of the oxide film, so that the detection is
safer, more efficient and more reliable; in case of failure of a certain measurement unit, the device still can complete the measurement work.