Abstract: The flow behavior and microstructure evolution of Al₂O₃/Cu composites, which conducted at deformation temperature of 300-900℃ and strain rate of 0.01-10 s^-1, were investigated by using Gleeble-1500 thermal simulator and TEM analysis. A constitutive equation of the peak value yield stress-deformation temperature-strain stress was also defined based on the Zener-Hollomn parameter and Arrhenius equation. The results show that the stress-strain curve of the composites is a typical softening mechanism of dynamic recrystallization type, and the curve consists of work hardening, dynamic softening and stabilization stage. The peak value of stress decreases with the increase of deformation temperature or the decrease of strain rate. In addition, the material parameters of the composites are obtained as follows:the structure factor ln A of 15.2391, the stress level parameter α of 0.020788 mm²/N, the stress exponent n of 5.933035, and the deformation activation energy Q of 2.1697×10⁵ kJ/mol. With increasing of deformation temperature, the dislocation density in the matrix is gradually decreased, and an obviously recrystallization feature appears. However, in the case of isothermal compression, the dislocation density is increased at first, and then decreased, with increasing of strain rates. According to the microstructure evolution and hot processing maps, the optimum processing condition for good hot workability of Al₂O₃/Cu composites can be summed up as:temperature range 500-850℃ and strain rate range below 0.1 s^-1.