Abstract: The Marx generator produces high-voltage pulses through parallel charging and series discharging. However, energy loss in the storage capacitors during discharge often leads to voltage droop, degrading pulse flatness. To address this, a Marx generator with a compensation circuit is developed. Fully-controlled IGBT solid-state switches are employed to regulate capacitor charging and discharging, and an independent voltage compensation loop is designed to suppress droop during the pulse. Simulation results show that with a main storage capacitor charged to 4 kV and a front-end capacitor charged to 1.1 kV, a single module delivers a 4 kV, 1 ms high-voltage pulse with droop effectively constrained to below 1.5%. This design markedly improves energy transfer efficiency and output quality of the pulsed power supply, demonstrating clear application value.