Abstract: The 93W-4.9Ni-2.1Fe alloys with addition of 0.15% La and Ce were prepared by powder metallurgy method. The microstructures and mechanical properties of the 93WNiFe alloys were examined, and the strengthening mechanisms were investigated. The results indicate that the addition of micro La and Ce into the 93 tungsten alloys can remarkably improve the dynamic mechanical properties of the alloys. The main strengthening mechanisms include the decrease of the free impurity elements of oxygen and sulfur in the alloys, reduction of the contiguity of tungsten grains, and tardy growth prohibition of the tungsten grains during the sintering process.