High-current pulsed electron beams (HCPEB) irradiation is a new potential method to polish hard steels and alloys. After HCPEB machining, the performance of machined surface, such as corrosion resistance and micro-structure, has been greatly improved. Because of its good performance, HCPEB irradiation is playing more and more important roles in polishing hard steels and alloys. However, it is not clear about the energy density of HCPEB under different beam conditions. In this study, experiments have been conducted to investigate the formation of HCPEB and its energy density. Then, effects of argon gas pressure and the applied voltage to solenoid coil on the formation of HCPEB are analyzed. Finally, a mathematical model is developed to describe the relationship between five dominant beam parameters with the energy density of HCPEB, which has a good accuracy in comparison to the experimental results.