The invention discloses a high-voltage pulse capacitor constant current charging device and method; the device comprises an energy storage module and a discharge control module; the energy storage module comprises a plurality of energy storage units; the discharge control module comprises discharge control units matched with the energy storage units; the energy storage module serves as a power supply charging a load, and the discharge control units connect in series with the energy storage units back to a charging loop, thus realizing constant current charging for the load. The method monitors a charging current, and the energy storage units are connected in series through the discharge control module, thus accurately controlling the load charging voltage, and keeping the constant charging current. The energy storage units serve as the charging power supply of the load, thus solving the problems of high capacity requirement of a power grid access point in the prior art that the charging power is directly from the power grid; the charging control module controls an output of the energy storage module, thus realizing low voltage input and high voltage output without needing a transformer.