The effect of Ag, Mg on microstructure and ageing characteristics of Al-Cu-L(i2197)alloy has been studied. Independent small addition of Ag to the alloy enhances peakaging strength to a larger extent and the different aging-strengthening effect is accompanied by the different concentration of Ag. 2197 alloy has the largest solution-strengthening effect and the strongest aging response and aging- strengthening effect by the combined addition of Ag and Mg. Independent and combined roles of small addition Ag and Mg can be interpreted in terms of the solute-vacance interaction and solute-solute atom interaction.