A CVD (chemical vapor deposition) reactor is disclosed to include a reaction chamber, a gas heater, a substrate holder, a substrate heater, hot filaments, an electric field generator, and a magnetic field generator. By means of preheating applied gas with the gas heater and heating the substrate with the substrate holder and the hot filaments, the gas and substrate heating speed is accelerated, thereby saving much deposition time and greatly improving deposition efficiency. Matching with the electric field generator and the magnetic field generator, the ionization of applied gas in the reaction chamber is enhanced and, the uniformity of the thickness of deposition of metal substance on the surface of the substrate(s) is increased.