Abstract: In this paper, the microstructures parameters of immiscible Al-Pb alloy such as lattice constant, grain size in high energy ball milling process were studied by X-ray diffraction and SEM. The results show that the Pb(Al) solid solution can be attained by Mechanical Alloying in despite of their immiscibility and large difference in specific density. And the experimental result implies that by high energy ball milling the grain of Al and Pb were reduced to nanocrystalline. The observation of fine Pb grains spreading all over the place in Al base would benefit for preparation of Al-Pb system with better bearing properties.