The Cu-1.1Cr alloys performed in this paper were prepared by thermal deformation + solution treatment + cold deformation + aging treatment + machining. The flow stress behavior of Cu-1.1Cr alloy was investigated by isothermal compression on Gleeble-1500 hot simulator in the temperature range of 400-800°C and strain rate of 0.01-1s-1. The experimental results indicated that the flow stress of Cu-1.1Cr alloy depends on the strain rate and the deformation temperature. The flow stress increased with increasing strain rates and decreased with increasing temperature. The flow stress of Cu-1.1Cr alloy during hot compression deformation could be represented by Zener-Hollomon parameter including the Arrhenius term. The values of n, α and A in the analytical expressions of flow stress are fitted to be n=15.696, α=0.005178MPa-1 and A =1.289×1021s -1, respectively. The hot deformation activation energy is 346.738kJ/mol. The constitutive equation of the Cu-1.1Cr alloy was obtained .