In-situ co-precipitation method was adopted to get precursor powder CuWO4-Cux(OH)yCO3 in which the elements content was controlled precisely by using Na2CO3 at high temperatures. Fine Cu-20%W composite powders were obtained through subsequent two-stage hydrogen reduction. The structure, phase composition, distributions of elements and particle size of the prepared powders were characterized. The results showed that the pale green precursor powders mainly consisted of CuWO4 and Cu4(OH)6CO3 under the reaction conditions of pH 5, temperature 75℃, the (NH4)2WO4/Na2CO3 molar ratio of 1/10.578 and the reaction solution 300 mL. The element recovery rate reached 95%. After two-stage hydrogen reduction of 0.5 h at 450℃ and 0.5 h at 600℃, the composite powder particle was nearly spherical in shape with a size of 400~800 nm. Copper was semi covered by tungsten and the two elements distributed uniformly.