Al

2

O

3

/Cu composites were prepared by internal oxidation of Cu-Al sheet at 900 ℃ to investigate the microstructure and properties of the composites

in which the Cu

2

O powder was used as oxidizer. The results indicate that the Al

2

O

3

particles are dispersively distributed in the diffusion zone. The grain size in surface and inner of diffusion zone is sharply different

finer in the surface than in the inner. The micro-hardness of surface of diffusion zone can be improved due to Al

2

O

3

disperoids strengthening Cu matrix. Compared with solid soluted Al atom in Cu matrix

the Al

2

O

3

disperoids has slightly affected the electron diffraction

resulting in the increase of electric conductivity after Al

2

O

3

precipitation. With increase of deformation rate of Al

2

O

3

/Cu sheet in case of cold working

the tangle of Al

2

O

3

disperoids with dislocation becomes worse and worse.