The invention discloses a preparation method of coated copper-silver metal powder which contains the pretreatment of copper powder, the preparation of silver solution and the preparation of copper-silver metal powder, wherein the preparation method of copper-silver metal powder comprises the following steps: dropwise adding dilute nitric acid in the sol of copper powder to adjusting the pH value to 3.0-5.0, adding ionic masking agent with the dosage of 1-30g/L, fully stirring, injecting inert protective gas such as nitrogen, argon or the like to remove the air in a reactor for protection, then slowly dropping silver nitrate solution in the sol of copper powder while stirring to fully react for 30min, then dropping dilute ammonia water to adjusting the pH value to 7.0-11.0, continuously reacting for 30min, washing the reaction solution with deionized water, 5% of dilute sulphuric acid and ethanol solution for several times after the reaction and drying the obtained copper-silver metal powder at 60-80 DEG C to obtain the finished product. The product obtained by the method of the invention has excellent high temperature oxidation resistance and conductivity and narrow particle size distribution.