Alumina were fabricated by digital light processing (DLP) with alumina powders. Alumina surface morphology, microstructure and properties were studied by scanning electron microscopy and performance test system of electron gun assembly, respectively. The results indicate that DLP alumina has the characteristics of high density and conductivity. The heat transfer in electron gun assembly includes heat conduction and heat radiation. The heat transfer mode of DLP alumina was heat conduction and heat radiation, indicating high heating efficiency, compared to that of the alumina(heat conduction) by the existing technology.