The molybdenum sheets doped with different contents of La2O3 (Mo-La2O3) were prepared by powder metallurgy and processing technology. Then their mechanical properties were tested by use of tension at room temperature with different velocity and their microstructures were discussed by means of SEM, TEM and XRD. It is shown that both the strength and ductility of molybdenum sheets are greatly improved by addition of La2O3. The maximum elongation of annealed Mo- La2O3 sheets is up to 46%. The experimental results can be reasonably explained by the interaction of La2O3 particles and dislocation as well as the toughening of second phase La2O3 .