The effect of beryllium (Be) on the precipitation behaviors and mechanical properties of Al-Cu-Li-Mg-Zr-(Ag) alloys was investigated. The results show that adding 0.02 %Be to Al-Cu-Li-Mg-Zr-(Ag) alloys, the elongation of the alloy increased without significant decrease in strength and the aging response was accelerated. In a Al-Cu-Li-Mg-Zr-(Ag) alloy, G.P. zone was formed at early aging time (2 h) and T-1 and theta' phases were formed at peak-aging and over-aging times, while in Al-Cu-Li-Mg-Zr-(Ag)-Be alloys T-1 and theta' phases were formed at early aging time (2 h) and the density of theta' phase was very low and fine T-1 phases were homogeneously distributed at peak-aging and over-aging times.