Cu-Gd2O3 composites were prepared by the spark plasma sintering apparatus, and the research was mainly focused on physical properties and the interface reaction layer in the composites. The Gd2O3 powder distributed in the composite dispersively, and with the increase of the amount of Gd2O3 a three-dimensional grid structure formed in the matrix. New phase Gd2CuO4 was detected by XRD analysis, and the interface reaction between Gd2O3 and Cu matrix during sintering process was observed by TEM. The thickness of reaction layer and transition zone became broaden with the increase of the temperature. It was an effectively way to improve the mechanical properties of materials by the control of the thickness of reaction layer.