In order to improve the reactivity of submicron aluminum powder， Al-Cu composite metal powder was prepared by means of electric explosion composite wires. The preparation parameters were determined by monitoring the waveform with oscilloscope in the electric explosion process. The structure and morphology of the composite was characterized by X-ray powder diffraction（XRD）， scanning electron microscope（SEM）， transmission electron microscope mapping（TEM-MAPPING） and X-ray fluorescence spectroscopy（XPS）. The Al-Cu composites powder was consisted of CuAl₂ and Al. The morphology of the material was sphere with an average size 150 nm. The forming mechanism of the morphology of the as-prepared composite particles was analyzed. Both DSC and aluminum-vapor methods were employed to evaluate the reactivity of the material. The first oxidation peak temperature of Al-Cu composite metal powder was 550 ℃， as shown in its DSC curve. This parameter was decreased by 50 ℃ comparing with Al prepared with the same parameters. This results indicated that as-prepared composite particles had better reactivity. The first oxidation process of Al-Cu composite metal powder lasted from 500 ℃ to 600 ℃ within 5 mins， while the counterpart lasted from 500 ℃ to 650 ℃ within 7.5 min. Comparing with Al， the heat release rate of Al-Cu composite metal powder was increased by 33% during the first oxidation process. The reaction completeness of the as-prepared composite particles was 0.88 tested by aluminum-water reaction method， but it was only 0.73 for the counterpart. During the first 10 mins of aluminum-vapor reaction， the reaction completeness of Al-Cu composite powder was 0.36 which was as much as ten times that of the counterpart. The result suggested that the reactivity of the composite was improved a lot.