The invention discloses a method for forming a high-temperature stable coating on the surface of diamond. The method comprises the steps that Si powder, Co powder and TiC powder or WC are mixed and then subjected to ball milling, and metal mixed powder is obtained; diamond micropowder with the surface coated with a silicon layer is evenly mixed with the metal mixed powder and an organic solvent, and mixed slurry is obtained after drying; the mixed slurry is heated for a reaction, and the diamond with the surface coated with the high-temperature stable coating is obtained. According to the method for forming the high-temperature stable coating on the surface of the diamond, since silicon carbide and the metal layer with high-temperature stability are formed on the surface of the diamond micropowder, the bonding strength between the metal alloy plated layer and the diamond can be obviously improved, and the method can be used in a high-temperature occasion.