Capacitor charge power supply (CCPS) based on homopolar inductor alternator (HIA) has been successfully used in capacitor-based pulsed power supply (PPS), but there is still no perfect system modelling and compete system parameter design method. In this study, the system modelling and mode analysis of HIA-CCPS is developed in detail. First, a simplified CCPS model is proposed based on the voltage-behind-reactance (VBR) model of HIA and the phase base-value system (PBVS). Second, four different modes of CCPS are derived on conditions of the constant voltage load (CVL) assumption; the symbols and terms in these modes are unified. The equations derived in this study are the basis of the system parameter design and the further research of HIA-CCPS.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.