Abstract: The effect of pressure, gas atmosphere and W particle size on the shrinkage kinetic curve of nano-scaled W-Cu composite powders during hot pressing were studied. The growing of W grains in W-Cu alloys was analyzed. Some mechanical properties were measured. The results show that, using composite nano-powders of W-Cu, the nano-scaled W-Cu alloy in which W particle size is not more than 0.5μm can be obtained through hot pressing in H2 atmosphere and under a high pressure of 75 MPa at low sintering temperatures of 970-1200℃. The relative density of the ultrafine grained alloy can reach 98.8%. The mechanical properties at 500℃ greatly exceed those of the conventional W-Cu alloy.