The invention relates to bioactive nanopowders to be employed in bone reconstructions and to a process for preparing the same. According to the invention, the nanopowders are presented as chemically and structurally homogeneous particles with high crystallinity and a diameter of less than 50 nm, where the substituting ions are 0.75-2% Mg, 0.01-0.5% Zn and 0.01-0.5% SiO. The claimed process consists in precipitating a hydroxyapatite suspension in emulsion, under vigorous stirring at a temperature of 40...80°C and a pH value of 9.5...11.5, at an inorganic phase : organic phase ratio of 1 : 2...4 of an emulsion containing soluble salts of Ca, Mg, Zn, SiOand PO, separating the precipitate, redispersing the same in water with addition of 0.1...0.5% phenol ethoxylate and cow's milk whey (Z) as a dispersing agent in a ratio of 1 : 1.5...2 m/m, separating the precipitate, redispersing the same in water in a ratio of 1 : 100...150 with addition of polyacrylic acid as a sintering preventing agent and Ca(OH)for precipitation, the precipitate being finally heat treated at a temperature of 600...1300°C, while removing CaO and organic compounds traces.
