The hot deformation behaviors of single- and two-phase CuAlMn shape memory alloy were studied. Isothermal compression tests were conducted at different temperatures from 400°C to 800°C and various strain rates from 0.001/S to 1/S. At the temperature below 500°C, CuAlMn alloy had a two-phase microstructure (FCC α phase + L21β phase); while at the temperature higher than 550°C, the alloy had a single β phase structure. The flow stress curves showed the stress drop for all samples, indicating a dynamic recrystallization (DRX) feature of the alloy. The local minimum value of stress drop appeared at 500°C. The thermal active energy (Q) were calculated to be 418.7 kJ mol−1 for α+β alloy at 400–500°C and 219.7 kJ mol−1 for β alloy at 550–800°C, respectively. The artificial neural network (ANN) model showed a high precision to predict the flow stress of the studied alloy at a wide range of temperature. Based on the dynamic material model (DMM) theory, the processing map of the alloy that consists of the contour lines of the power dissipation factor, η, and the instability criteria was established. The grains were refined to a micron level and DRX of α phase occurred during the deformation between 400–500°C at the low strain rate. The hot deformation behaviors of the alloy at the low temperature (400–450°C) mainly depended on the deformation of α phase. The optimum deformation parameters for the single-phase CuAlMn alloys were 750–800°C/0.1–1 s−1.