Development trends of pulsed power technology is high power density, compactness and high reliabilities. Liquid dielectric, because of its high insulation, easy flow, fast recovery and good heat dispersion, is widely used in the pulse power source based on liquid pulse forming line as energy storage medium. Research focuses are put on the key techniques of the ARC series of pulse power sources. Studies are carried out on pulsed breakdown characteristics, system development and its application. Firstly, a pulse formation line is proposed based on high-energy-density-storage liquid dielectric and slow wave structure. By using the method of electromagnetic field uniformity and insulation technology to solve the high-voltage insulation problems, the compact pulse power sources ARC-01/02 are developed. They can output 1-2 GW power, 5-30 ns duration, 1-100 Hz rep-rate, and their maximum compact level is increased by 2 times that of the international advanced similar devices. Through the research on the pulsed insulation characteristics of liquid dielectric in the microsecond regime, the database is established by statistical analysis method. And then, by using the ultrafast camera optical diagnosis method, based on the images of generation, propagation, cut-off for shock wave, sub-microscopic fracture surface, a liquid dielectric breakdown model is established, combined with amorphous energy band and Griffith tension theory. Finally, the pulsed power source is applied to drive wide band/narrow band microwave source and test the stability and life of carbon fiber cathode.