The preparation of CuCr25(C)and CuCr25(W)alloys by vacuum inducing melting is presented in this paper.The influen ce of different alloy elements(C&W)on Cr-crystalline grain is studied.And the sequent effects on the physic al properties and breakdown voltage are also discussed.It is found that the mechanical strength and the voltage withstanding stress have been improved for the alloys with adding of C or W.