Neutral beam injection is one of the main auxiliary heating methods in controllable nuclear fusion experiments. During the operation of the EAST neutral beam injector, a large amount of energy is deposited on the ion source components, especially the electron dump (ED). In this paper, the energy deposited on the ion source components was analyzed in arc discharge mode and beam extraction mode indirectly by calculating the energy taken away by the cooling water. The results show that the ED has a large heat load: the average power density is almost 4.5 MW/m2 when the beam power is 3.3 MW. This research may lay the foundation for increasing the heat transfer capacity and guide the optimization of the ion source components in future work.