Research about the 91tungsten alloy deformed by hydrostatic extrusion is carried out. The relations between the microstructures, mechanical properties of the 91tungsten alloy after deformation and the deformation amount were studied. The results show that the ratio of the long-short axis of tungsten particles and the strength of tungsten alloys increase along with the increase of the deformation amount, the valid contiguity of tungsten particles and the elongation ratio and contraction ratio of area of tungsten alloys decrease along with the increase of the deformation amount. Both the increment and the decrement become smaller and smaller along with the increase of the hydrostatic extrusion deformation amount.