Abstract:he effects of two kinds of rare earth elements La and Yon the size as well as the morphology of tungsten particles during hydrogenolysis were investigated by using SEM, X-ray difftaction and IP(Instrument-determination of powder and porous-material). The results indicated that in tungsten powders, the La and Y exist in the forms of oxides(La2O3, Y2O3) and tungstates (La2W2O9, Y6WO(12)) and the most of tungsten powders are regular polyhedrons. The existence of La and Y hinders drastically the growth of tungsten particles during hydrogenolysis of blue W oxide, and the effect of Y is greater than that of La.