A radar scanner capable of monitoring blast furnace burden surface variations in real time is mounted in a proper position so as to ensure real-time capability and truthfulness of blast furnace burden surface imaging, a radar antenna extends into the interior of the blast furnace, through mechanical design of a transmission device, the rotation of an antenna is controlled, position selection is achieved, and with the consideration to an optimal visual angle range and an optimal distance measurement range, scanning to half of the furnace burden surface is achieved.