In order to deeply understand the high temperature deformation behaviors of Cu–0.23%Al₂O₃ (volume fraction) alloy, the changes of flow stress and microstructure for this alloy after deformation at high temperatures were investigated by using the Gleeble–1500 hot simulator, metallographic microscope and transmission electron microscope. The results show that the flow stress will change significantly with the thermal compression conditions and is mainly divided into three different stages. In addition, the average activation energy and other material parameters of this alloy deformed at high temperatures were obtained, based on them, the constitutive equation of the peak value yield stress–strain rate–temperature was also established. With increasing of compression temperature, the size and number of dynamic recrystallization grains are increased. However in the case of isothermal compression, with increasing of strain rates, the evolution of metallographical microstructures becomes disequilibrium, the size of subgrain is gradually decreased to about 0.5—1 μm, and the dislocation density is increased at first, and then decreased.