The activated surface of 60-㎛ alumina powders was chemically plated to form nickel- phosphorous films by slow addition of the reactants-nickel salt and sodium hypophosphite solutions. This semibatch type of reaction mode could control the plating rate easily and guarantee the adhesion of the film to the powder surface and the suppression of the undesirable particle production in broader range of the plating conditions. The semibatch type also made it possible to prepare the plated powders with better chemical, electrical and magnetic properties. The pH of the reacting system, the molar ratio and the input rate of the reactants had great effects on the rate of plating, the electrical resistivity, the chemical composition, the adhesion and the magnetic property of the film.