In this paper, the high temperature tensile tests and ambient temperature tensile tests are performed. The high strength of the welding for 1Cr9Mo/45 and 0Cr18Ni9/45 is somewhat smaller than the ambient strength, but the elongation is improved. Both the high strength and ductility are decreased compared to the results of the room tests. The rupture is located in the side of 1Cr9Mo for the welding of 1Cr9Mo/0Cr18Ni9 at the room temperature, while the rupture is located in the side of 0Cr18Ni9 at high temperature. It is concluded that the strength in high temperature is decreased for 0Cr18Ni9. The rupture happens in the side of 45 for both heterogenic welding joints of 45/0Cr18Ni9 and 45/1Cr9Mo.