A preparation method of a nano-silver particle coated by a novel 
macromolecule protective agent belongs to the technical field of manufacture of printing 
electronic materials. The steps comprise that a) a solution of the 
macromolecule protective agent with a certain temperature, a certain concentration and a certain pH value is prepared; b) a silver 
ammonia solution and a reductant solution are added into the 
macromolecule protective agent solution; c) the 
mixed solution is stirred, the pH value of the 
mixed solution is monitored in a real time, and the pH value of the 
mixed solution is kept to exceed 7 by adding a pH modifier; and the nano-silver particle can be prepared through a 
chemical reaction. In comparison with the prior art, the preparation method of the nano-silver particle coated by the novel macromolecule protective agent provided by the invention has the beneficial effect that acrylic-based resin with a multi-carbonyl structure is taken as the protective agent for the nano-
silver preparation in an alkaline environment, wherein no research report has been proposed domestically; and because of outstanding 
aging resistance (such as the resistance to 
corrosion of acids, weak alkalis and salts) and 
adhesive force of the acrylic-based resin, the prepared nano-silver particle can guarantee requirements in applications for the 
adhesive force and the 
aging resistance without addition of other types of resin.