Composite heat screen for reduction furnace and reduction furnace

The utility model provides a composite heat screen for a reduction furnace and the reduction furnace. The composite heat screen comprises a metal guard plate, a first nickel-chromium-based alloy plate, a composite insulation board and a second nickel-chromium-based alloy plate which are sequentially vacuumized and laminated into a whole; and the surface of the first nickel-chromium-based alloy plate laminated with the metal guard plate is coated with a silicon carbide coating. The metal guard plate is used for protecting the silicon carbide coating on the surface of the first nickel-chromium-based alloy plate, so that the silicon carbide coating is prevented from being damaged by a fallen silicon rod, the service life of the heat screen is prolonged, corrosion of hydrogen chloride produced in the polycrystalline silicon production process to the silicon carbide coating is prevented, and the reduction furnace atmosphere is prevented from being polluted; the first nickel-chromium-based alloy plate is used for s