The researches on affecting factors of preparing Al/PS microcapsules with in situ dispersion polymerization of styrene were carried out. The composition of reaction system including amounts of monomer,initiator,stabilizer and nano-aluminium particles had great influences on the morphology,size and distribution of Al/PS microcapsules. On the basis of reaction rules,uniform Al/PS microcapsules were prepared under optimization conditions. These conditions were amount of nano-aluminium particles less than 5%,amount of styrene 20%,and the amount of initiator and stabilizer 0.5% and 1.5% based on amount of monomer,respectively. The Al/PS microcapsules had good sphericity,smooth surfaces and well dispersibility. The size of Al/PS microcapsules was 1.345 μm,and the dispersion coefficient was 13.1%.