Abstract: Taking Cu-Al alloy powder as raw materials,Al2O3/Cu composite was prepared by reaction milling and spark plasma sintering. The morphology and phases of alloy powders after milling were studied,as well as the effects of Al contents on microstructure and properties of the composite. The results show that the spheroid powder particles with the size of 2-5 μm were generated after milling for 20 h,Cu phase diffraction peak exhibited obvious broad,and α-Al2O3 nano-particles were generated in situ in Cu matrix. The size and distribution of Al2O3 particles were affected by Al contents,and Al2O3 particles gradually grew up,enriched and agglomeration with the increase of Al contents. Relative density and electrical conductivity of the composite decreased gradually with the increase of Al contents,but the microhardness increased. When the Al content was 0.7wt%,the composite owned the best overall properties.