Nano-aluminum/polystyrene(PS) microcapsules with different aluminum content were prepared under optimization conditions. With increasing amount of nano-aluminum particles,the encapsulation ratio of microcapsules decreased. The nano-aluminum/PS microcapsules had good sphericity,smooth surface and high dispersibility. The activities of nano-aluminum powders were analyzed before and after encapsulation. The nano-aluminum/PS microcapsules with different aluminum content had almost equal activity. The active aluminum content of nano-aluminum/PS microcapsules was 76.07%. Stored in a sealed bag in natural condition and in an oxygen bottle after 30 d,the active aluminum content of nano-aluminum/PS microcapsules were 76.06% and 74.81%,respectively. The results show that the active aluminum content can keep for long time after aluminum was encapsulaed by PS.