Abstract: Cu/Al composite plate was prepared by roll-cast process, and then was annealed at 250, 300, 350, 400 ℃ ( for 3 h ), the effects of annealing temperature on interface microstructure, phase and mechanical properties were studied. The results show that, intermetallic compound formation at interface was promoted by annealing, CuAl2 gathered at Al plate side and Cu9Al4 gathered at Cu plate side, the cracking in the processes of 90° peel and tensile was conducted along intermetallic compound, a diffusion layer with a certain thickness was good for interface bonding of composite plate. The best annealing process for Cu/Al composite plate was 300 ℃×3 h, by the process, the diffusion layer reached 2-3 μm thickness, and tensile strength and elongation of the composite were 109.7 MPa and 31.8%.