Abstract: By using the concept of electromagnetic energy, a systematic description is given for pulsed power generation process. The physical characteristics of energy storage, transmission, and output have been examined with a unified theoretic model. From the characteristic impedance point-of-view, the difference and relation among key pulsed power components have been discussed. According to the theoretical understanding, description and explanation have been given for several typical pulsed power generation schemes, including pulse forming line, pulse compression, and flux compression.