This paper presents the design and verification of a portable resonant voltage doubling capacitor charging power supply with an input voltage of 24 V and an output voltage of 3 kV. According to the characteristic of high voltage ratio, this power supply adopts a topology structure combining the series resonant topology and the voltage doubling rectifier, which avoids the adverse effects of excessive number of turns on the secondary side of the high frequency transformer and excessive distributed parameters. The core components such as high frequency transformer, resonant capacitor and switching device were designed and debugged. The power supply was used to conduct the capacitor charging experiment, and the test results have verified the correctness of the design.