The invention relates to a method for preparing silver-coated copper powder used for low-temperature paste, which belongs to the technology field of surface treatment. The method comprises the following steps: copper powder balls are ground to D50, namely 10 to 20 micron, oxidizing layers are removed through acid washing, then deionized water is used to ensure the copper powder to be washed to beneutral, water and dispersant are added for even stirring, acidic silver-contained solution is added in the copper powder paste so that cyanide-free chemical silvering reaction is performed, and after the reaction is completed, the silver-coated copper powder product provided with 20 to 45 percent of silver content and used for low-temperature paste can be obtained through cleaning, surface modification, drying and sieving treatment. The method has the advantages of high silvering efficiency, even coating, simple process and low production cost. The electric volume resistivity of the silver-coated copper powder prepared by the method is 2 to 3*10-4 omega cm, and the silver-coated copper powder can be partly or fully replace the pure silver powder in the low-temperature electronic paste field.