A vacuum melting furnace for infrared glass, includes an upper furnace body and a lower furnace body that can be connected with each other or isolated from each other. Vacuum melting of the infrared glass is achieved in the upper furnace body wherein the influence of water in the environment is eliminated. The vacuum negative pressure environments can promote separation of hydroxyl in the structure, which achieves removing of hydroxyl in the glass, and then discharging of the molten infrared glass is conducted at atmospheric pressure in the lower furnace body. By using the vacuum melting furnace for infrared glass, infrared glass with good spectrum transmission performance can be obtained with improved property stability and optical homogeneity, which facilitates the preparation and molding of large sized and special-shaped infrared glass products.