W-20Cu ultrafine composite powder, whose average grain size was about 500 nm, was fabricated by spray drying and calcining-continuous reduction technology. In the W-20Cu ultrafine powder the nanocrystalline Cu grain can wet W grain by the CuO transitional layer, the special non-metal-metal nanocomposite structure would play very important roles in obtaining W-Cu alloy with good mechanical properties, thermal conductivity and homoaeneous microstructure. (c) 2007 Elsevier B.V. All rights reserved.