Abstract: A 99.99% silver material is manufactured by adding 8×10-5Mg to the 99.995% Ag.The test measurement of mechanical properties for this material shows that the strength and hardness of the silver kept at 25℃ for 200 days do not change with time if ε =98%.By adding trace magnesium to 99.995% silver,the pellets of solid solution of Mg dissolved by Ag are produced with fine crystal grains of Ag,increased crystal interfaces and higher strength.