Silicon boron nitride (SiBN) has been paid attention extensively due to its high melting point and anti-oxidation, which is also the reason that one of the research focus is its physical property of this material at high temperatures. It has been reported that amorphous SiBN ceramics could be modeled based on the the atomic structure of -Si3N4. In this paper, the molecular dynamics and DFT calculation were employed to explore the structural model of SiBN, to reveal the electronic and optical properties of SiBN at high temperatures. It is worth noting that, different from -Si3N4, the absorption of SiBN at visible light and higher frequency decreases at higher temperatures, and the reflectance decreases to 1% or so. Such results could not be found in single crystalline Si3N4. These indicate the possibility of SiBN used as the stealth coating. It also could be a good candidate in the optoelectronic application of amorphous materials in the near future.