A two-pole two-phase passive compulsator is designed, whose magnetic field is built by permanent magnet. The compulsator’s no-load and discharge magnetic characteristics are analyzed by using finite element software. The Nd-Fe-B material is adopted as the permanent magnet, in thickness of 12 mm. The maximum magnetic flux density in the air gap is 0.443 T at the no-load state. At the designed rotor speed of 60 000 r/min, the single-phase open circuit peak voltage and the core loss power are 195.4 V and 599 W respectively. The single-phase discharge, two-phase parallel discharge and two-phase series discharge processes are simulated separately, to a small impedance load at 1 mΩ, 1 μH. The peak value of single-phase discharge current is 10.90 kA, and the pulse width is 0.78 ms. For two-phase parallel discharge, the peak current value and pulse width are 14.64 kA and 1.1 ms respectively. For two-phase series discharge, the peak voltage rises to 333.7 V, while the peak current drops to 8.95 kA. The compulsator’s energy storage is greater than 4 MJ, whose pulse power is greater than 2 MW. The alternator has compact structure, high energy and power density.