The phases formed by erbium in alloys with 5.6%Zn, 1.9% Mg, 1.6% Cu,1.0% Li,0.3% Er(wt%) is investigated by TEM. Most of erbium is formed with aluminum to Al3Er phases which look like block, dot, lath or worm. Some of Al3Er phases are coherent with alloys matrix, and fine Al3Er phases can be sites for ? (MgZn2) heterogeneous precipitation. Saturated erbium is segregated to grain boundary seriously and there is small Al3Er phase in grain boundary, where precipitates are not continuous.