The invention belongs to the field of microwave sintering, discloses visual microwave sintering equipment for cathodes, and provides a small microwave sintering furnace and a microwave sintering heat preservation device special for scandium-tungsten cathode sintering. The visual microwave sintering equipment for the cathodes is mainly composed of a microwave source, a heat preservation device, a stainless steel heating cavity and a visual protective atmosphere space. The heat preservation device comprises a thickened heat insulation base, a one-layer corundum crucible, aluminum oxide fiber cotton, a two-layer corundum crucible, a tungsten oxide layer, a three-layer corundum crucible and a corundum cover with holes. The heating cavity directly carries out energy conversion through the microwave source with the power of 3 KW, microwaves can be conveyed into a sample, and an infrared temperature measuring device is arranged at the top of the cavity. The visual protective atmosphere space is connected with a vacuum and atmosphere control system to provide an accurate controllable atmosphere for sample sintering. The visual microwave sintering equipment for the cathodes has the advantages that the sintering process is visual, and the repeatability is high; the high-purity tungsten oxide layer avoids pollution to the cathodes, and the microwave ignition phenomenon can be prevented; and the microwave field intensity is uniform, and the uniform sintering of the cathodes is realized.