To reduce the energy loss of the air-core pulse alternator and the heating of the field winding, a field circuit topology with the function of recovering residual magnetic energy is proposed. By setting the adjustable inductance in the capacitor branch, the capacitor after the discharge has a reverse voltage, forcing the thyristor and the diode to turn off, and switching the current flow path to realize the transfer of the remaining excitation energy to the capacitor. The circuit uses the thyristor as the main switch, and its high current turn-off capability gives it an advantage in the application of high-power pulse alternator. The working process of the proposed excitation energy recovery circuit is introduced, the influence of residual energy recovery on the energy loss and heat generation of the field winding is simulated and analyzed, and the working principle of the circuit topology is verified experimentally. The results show that the circuit can quickly recover the residual energy in the field winding, shorten the freewheeling time of the excitation current, and reduce the excitation loss and energy loss. The law reflected by the simulation and experimental results is consistent with the circuit principle, which shows the validity of the circuit method.