The traditional CuW alloy prepared by single particle size of tungsten powder has been difficult to meet the requirement of electrical contact of the high-frequency switching capacitor switch.This experimen prepares CuW alloy with three kinds of particle size of tungsten powder (super rice, micron and submicron).The microstructures of CuW alloy were analyzed by field emission scanning electron microscopy and the arc breakdown properties of CuW alloys were investigated.The results show that CuW alloy prepared by grading tungsten powder can form a variety of W-W sintered neck which strengthened tungsten skeleton. This kind of tungsten skeleton makes the Cu phase more uniform and more dispersed.The hardness and electrical conductivity of the CuW alloy is 30~40% higher than the national standard, and the CuW alloy has a higher resistance of voltage strength.In addition,the bonding strength of the CuW/CrCu prepared by grading tungsten powder is 40~60% higher than the national standard.