The formation process and growth kinetics of the intermetallic (IMC) layers at the solid-state diffusion-bonded interface between the Cu and Al foils conducted by plasma activated sintering processing were investigated in the temperature range of 673-773 K. The results show that the formation process of the IMCs involves four stages, physical contact, IMCs nucleation, IMCs connection along the interface and continuous thickening of the IMC layers. The interfacial region is composed of Al4Cu9, AlCu and Al2Cu layers. The relationships between each layer thickness and the reaction time follow the approximate parabolic law, indicating the diffusion-controlled growth kinetic of the IMCs. The growth rate constants of the IMC layers conform to the Arrhenius relation with temperature, and the calculated activation energies for the growth of total IMCs, Al4Cu9, AlCu and Al2Cu layers are 80.78, 89.79, 84.63 and 71.12 kJ/mol, respectively.