The utility model relates to the technical field of wave-absorbing material testing, and discloses a wave-absorbing material flat plate
reflectivity testing device which comprises a flat plate sample table and a
horn antenna matched with the flat plate sample table, the flat sample table comprises a cylindrical rod, a base, a rotating track, a table top and an
inverted T-shaped
metal panel which are connected with one another; the
inverted T-shaped
metal panel is driven to rotate along the circumferential direction when the rotating track on the table top rotates; the testing sample is arranged on one side face, facing the
horn antenna, of a vertical panel of the inverted-T-shaped
metal panel, and when the rotating track rotates in the circumferential direction, the inverted-T-shaped metal panel is driven to rotate in the circumferential direction, or the angle between the vertical panel and a horizontal panel of the T-shaped metal panel is adjusted, so that the testing sample is tested. And direction angles and
pitch angles between the plane of the
test sample and the horn antennas can be adjusted. The device has the advantages of being flexible and convenient to use, small in occupied area, capable of achieving multi-stage adjustment, high in testing precision and the like.