The invention provides a method for improving stir-head wear resistance in friction stir welding of SiCp/Al composite materials. The method is characterized in that nano-diamond powder is brazed on end face of a shaft shoulder of a stir head and the surface of a stir needle to form a nano-diamond wear-resistant layer, and wear resistance of the shaft shoulder of the stir head and the stir needle is improved. The stir head has the advantages of high strength, high wear resistance and long service life.