A compact pulsed power driving source based on a Tesla transformer utilizing capacitive energy storage method is introduced. This pulsed power driving source has been designed for fast charging of transmission line switched oscillators or resonant antennas in order to improve their voltage capability and energy efficiency of generating high frequency oscillations. Firstly, the schematic and operation processes of the driving source are described. Then the influences of the key circuit parameters to the charging process of the load are analyzed by utilizing equivalent circuit method. And the engineering design of driving source has also been introduced. At last, the preliminary test results of the driving source and the experiment using this driving source to investigate the transformer oil breakdown characteristics under 10 ns pulse are introduced. It is shown that transmission line with an equivalent capacitance of about 15 pF is charged to a peak voltage of -224 kV within about 10 ns through a connecting inductor under the condition that the output spark gap switch closed when the intermediate capacitor is charged to -191 kV. It can be concluded that this pulsed power driving source satisfies the requirements for fast charging of capacitive loads such as transmission line switched oscillators to hundreds of kilo volts.