This paper presents the investigation of inductance mathematic model of Homopolar Inductor Alternator (HIA) in a novel pulse capacitor charge power supply. We study the characteristics of the inductance parameters based on the HIA theory and three-dimensional finite element analysis, establish the inductance mathematics model of HIA, and build a novel pulse capacitor charge power supply with 12/10-pole HIA. We also establish the simulation model of the power supply and compare the simulation results with the experimental. The results prove the correctness of the inductance mathematic model. Finally, the problem of parameters-matching between charging circuit and the HIA inductance is discussed.