The invention relates to a preparation method for a metal copper covered on the surface of ultrafine molybdenum powder or ultrafine tungsten powder, which belongs to the field of new materials. The preparation method is characterized in that the method mainly adopts the ultrafine molybdenum powder or the ultrafine tungsten powder with the average particle diameter D50 not more than 1.3 Mum, whichis mixed with Cu<2+> soluble salt solution under the continual stirring, polymeric surfactant of coordination group with N atom and O atom is added, one of hydrazine hydrate, sodium hydrosulfite or sodium hypophosphite is added as reducing agent, and an appropriate amount of alkali is dropwise added to adjust pH value in the period so that pH value of the reaction system is from 5.5 to 12.0; in addition, in the range of 20 to 95 DEG C, the reaction continues for 0.5 to 3 hours; the ultrafine molybdenum powder or the ultrafine tungsten powder is filtered through flushing by diluted NH4Cl or NH4NO3 solution, the powder is pulped by alcoholic solution with 0.2-3.0 percent of fatty acid, and the ultrafine molybdenum powder or the ultrafine tungsten powder is filtered again, the powder is heated and dried by H2, to prepare the ultrafine molybdenum powder or the ultrafine tungsten powder of the metal copper covered with the even surface. Through adjusting the proportion of soluble salt of the ultrafine molybdenum powder or the ultrafine tungsten powder and the copper, the ultrafine molybdenum powder or the ultrafine tungsten powder covered by metal copper with different composition proportions can be prepared to meet different demands.