The mechanical properties of molybdenum with 3wt% niobium single crystal materials (Mo-3Nb single crystal material) were tested by miniature disk testing method. It is found that the yield stress, the fracture strength and the micro-hardness of Mo-3Nb single crystal materials by Russian supplying were higher than those of the home-made ones, while the elongations of the former material were lower than the later material. However, according to the TEM morphologies, Nb component in Russian supplying materials was a little more than that in the home-made single crystal materials, and some bar-type strengthening phases were observed in Russian supplying materials. Therefore, the difference of the microstructures and the component may cause the mechanical properties difference of the two materials.