The coatings of W-Ti carbides on the surface of diamond was obtained by using physical vapor de-position (PVD), during which WO3 powders pre-treated with hydrofluoric acid were reduced by titanium hy-dride in vacuum at 850℃. The resistance of diamond to corrosion at high-temperature was investigated. The formation of W-Ti carbides on the surface of diamond was verified by X-ray diffraction analysis, the interface state between diamond and matrix in metal-base diamond composite was observed by scanning electron micro-scope. The results showed that the carbide coating is easy to be formed at low deposition temperature on the surface of diamond, while the resistance of diamond to corrosion at high-temperature and the strength of bond-ing between diamond and metal matrix are effectively improved.