Abstract: In this paper,the effect of internal oxidation on structure and properties of alloy has been studied by testing resistivity,resistance to corfosion,wear and compression and by surveying SEM and TEM morphology of internal oxidation strensthened Cu-Al alloy. The results show that in internal oxidation layer,the internal oxides grow along grain boundary in strip and laminar form,and in grain,there are Cu substrate and dispersed distribution of oxide particles. Internal oxidation decreases the quantity of solid solution of Al atom in substrate,lowers the esistivity of alloy and increases the density and dispersion strengthening effects. As a result the resistance to corrosion, wear and compression of 5% Al-Cu powder sintered alloy is improved.