The nanocrystalline powder of Al-15%Pb-4%Si-1%Sn-1.5%Cu (mass%) were prepared by mechanical alloying. Systematical investigations were carried out on the structural change, grain size, lattice constant, morphology of the powder and the chemical composition of the Al-15%Pb-4%Si-1%Sn-1.5%Cu high energy ball milled powder using X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy(SEM). The experimental results showed that the nanocrystalline powders were synthesized and the homogenous nanophases was achieved by mechanical alloying. The effect of ball milling was more evident to lead than to aluminum. The grain size of Pb was 40 nm after milling for 40 h, and the grain size of aluminum was 65 nm after milling for 60 h. The solid solutions of Al(Cu, Si) and Pb(Sn), and supersaturated solid solution of Pb(Al) were observed by MA. Otherwise, brittle element powder of silicon was more difficulty alloying in the mechanical alloying process.