The present work was aimed to examine the changes of the shape and particle size distribution(PSD) of δ` particles on ageing in Al-Li-(Cu, Zr) alloys which had low density, high specific strength and stiffness. Increasing ageing time and temperature resulted in particles whose aspect ratio tended toward 1. The aspect ratio of δ` particles was not dependent upon the ageing temperature and time in Al-Li-Cu alloy but was dependent upon them in Al-Li-Zr alloy. The PSD of δ` particles in Al-Li-Zr alloy skewed to the right hand compared with that in Al-Li-Cu alloy, because Al₃Zr phase in Al-Li-Zr alloy formed before ageing promoted the precipitation and growth of δ` phase. Therefore, the PSD of the δ` particles was found to be affected by the presence of Al₃Zr particles. The growth rate of δ` phase was not affected by the existence of the third transition phase T₁formed by the addition of Cu in Al-Li alloy but was affected by the existence of Al₃Zr formed by the addition of Zr in Al-Li alloy.