Hot deformation behavior of the 3003 Al alloy was investigated by conducting hot compression tests at various temperatures (300–500 °C) and strain rates (0.0l–10.0 s−1). A constitutive equation was established to describe the flow behavior. The apparent activation energy of the 3003 Al alloy was determined to be 174.62 kJ·mol−1, which is higher than that for self-diffusion in pure Al (165 kJ·mol−1). Processing maps at a strain of 0.6 for hot working were developed on a dynamic materials model. The maps exhibit a flow instability domain at about 300–380 °C and 1.0–10.0 s−1. Dynamic recrystallization occurs extensively in the temperature range of 450–500 °C and at the strain rate of 10.0 s−1. The optimum parameters of hot working for the 3003 Al alloy are confined at 500 °C and 10.0 s−1 with the highest efficiency (37%).