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A novel method for preparing aluminum/aluminum nitride ceramics (Al/AlN) substrates is proposed in this paper. The method included two processes: (1) the surface of AlN was coated with a CuO thick film and sintered; (2) Al foil was put on the pretreated (in process 1) AlN surface and bonded to AlN through pre-heating at 400 °C and final heating at 660 °C in N 2 -H 2 reduction atmosphere. The experimental results obtained by optical and scanning electron microscope (SEM) observations as well as by X-ray diffraction analysis at the cross-sections of the joints and the fracture surfaces, suggest that the reaction mechanism starts with the reaction of CuO with AlN to form CuAlO 2 , when the AlN coated with CuO is heat-treated at high temperature. A Cu layer is produced by the reduction of CuO and Cu diffuses in the Al foil, forming strong Al/AlN joints. Elongated crystals of Al 2 Cu are developed in the reaction zone at the interface between Al and AlN. The results of mechanical tests showed that the peeling-off strength of the Al foil from the surface of the AlN substrate reached a value of 15.4 MPa for the Al/AlN couples produced after 30 min of heat treatment at 660 °C. [ABSTRACT FROM AUTHOR]