Abstract: Microstructure of alloying Mo-3Nb single crystal materials supplied by Russia and China was analyzed, some bar-type precipitated phases were observed in Russian supplying materials, and there are few ball-type precipitated phases in the home-made single crystal materials, furthermore, the density of bar-type precipitated phases is much higher than that of ball-type precipitated phases. Otherwise, Nb component in Russian supplying materials is a little more than that in the home-made single crystal materials. At the same time, it is found that strength of the Russian supplying Mo-3Nb single crystal materials is higher than that of the home-made ones. Therefore, according to alloy strengthening mechanism, it is considered that microstructure and component are the main factors that influence the mechanical properties for alloying Mo-3Nb single crystal materials in room temperature.