Abstract: W-Cu contact materials treated by HIP have been investigated Contact materials were made by mixing, pressing, presintering and infiltrating. HIP was conducted at the temperature below melting point of copper and under the pressure of 90-100 Mpa. It has been proved that the density of W60Cu40 contact material after HIPing can be increased from 12.7-12.8g/cm³ to 13.2~13.3g/cm³,hardness from HRB 50-70 to HRB80, bending strength from 5.5~7.5×10² Mpa to more than 1×10³ Mpa and electric conductivity can be stably over 60% IACS. It is considered that the defects such as loose contact, shrinkage porosity and weak points of infiltration in workpieces can be elemented by HIPing. The mechanism of HIPing W-Cu contact materials is analogous to that of casting alloy. HIPing shows no effects for above mentioned defects, if they communicate to the surface. Experiments also showed that in increase of density HIPing had good effects for W-Cu materials with low copper contents of 20%.